Mutations of the P53 tumor suppressor gene as clonal marker for multiple primary lung cancers

OBJECTIVES: Second primary lung cancers are prevalent after treatment for initial lung cancer, and the lung is also one of the most frequent sites for recurrence after removal of early-stage lung cancer. The objective of the present study is to clarify the clonal origin of the second tumor with the p53 gene mutation used as a clonal marker. METHODS: Of 794 consecutive patients who underwent pulmonary resection for primary lung cancer from 1980 to 1993, 22 required second pulmonary resection during the follow-up period, with a median interval of 38 months. We examined 16 of these patients for mutations of the p53 gene occurring in exons 5 through 8 by the polymerase chain reaction/single strand conformation polymorphism method. Differential diagnosis was also made on a morphologic basis, considering the degree of cellular differentiation and cytologic subtypes. RESULTS: Nine of the 16 patients analyzed had at least one p53 mutation in their tumors. We were thus able to make molecular diagnoses for these patients. The mutational status of the p53 gene was discordant in all nine patients, suggesting a different clonal origin despite the fact that six of them had almost identical histologic features. CONCLUSIONS: Analysis of p53 gene mutations was thus useful in distinguishing second primary lung cancers from recurrent tumors. The observed heterogeneity of p53 status was also in line with the "field cancerization" concept.     

Analysis of loss of heterozygosity (LOH) at the p53 and Rb suppressor genes in urinary bladder carcinoma

Loss of heterozygosity (LOH) at the p53 and Rb genes, and its clinical correlations were examined in 58 urinary bladder carcinomas. DNA was extracted from formalin-fixed, paraffin-embedded tissues, and amplified by polymerase chain reaction (PCR). The LOH at p53 was examined by restriction fragment length polymorphism (RFLP), and the LOH at Rb by single-strand conformation polymorphism (SSCP). Among patients with urinary bladder carcinoma, 60.3% (35/58 patients) showed heterozygosity at p53 and LOH was detected in carcinoma in 60.0% (21/35), i.e., LOH in 61.9% (13/21) of superficial (< or = pT1) and in 57.1% (8/14) of muscular invasive carcinomas. Therefore, LOH at p53 was considered to occur before the beginning of muscular invasion. Except for the patients who died of other causes or were missed during the follow-up, 67.4% (29/43) showed 43.8% (7/16) died of carcinomatosis, but, only 15.4% (2/13) of the patients without p53-LOH died. The 5-year survival rate calculated by the Kaplan-Meier method was 76.9% in patients with heterozygosity at p53, and 25.1% in those with LOH at p53, being significantly lower at p < 0.05 in the former than in the latter. From an analysis of multiple bladder carcinomas, LOH at p53 occurred on the same allele in different tumors of the same bladder, suggesting the monoclonal origin of each tumor of multiple bladder carcinomas. On the other hand, 51.7% (30/58) of patients showed heterozygosity at Rb, and LOH was detected in 16.7% (5/30) of them, i.e., 6.3% (1/16) in superficial carcinoma and 28.6% (4/14) in muscular invasive carcinoma.     

Predictive value of p53 mutations analyzed in bladder washings for progression of high-risk superficial bladder cancer

To assess the value of p53 mutations in predicting the progression of superficial bladder cancer [transitional cell carcinoma (TCC)] and to define exactly when p53 mutations occur in the process of tumor progression, 80 consecutive bladder washings from 26 high-risk (indicated by quantitative karyometric analysis) superficial TCC patients were examined by single-strand conformation polymorphism. Six of 13 patients who experienced clinical progression (progression to T2 or higher) were found to have a p53 mutation in one or more of their bladder washings. In the control group (no progression to invasive disease), only 1 of 13 patients had a p53 mutation. For these high-risk superficial TCC patients, the occurrence of a p53 mutation has a positive predictive value of 86% for the progression of disease. A negative predictive value of 63% was observed. Moreover, because p53 mutations were found in samples prior to progression (mean, 8 months), they could identify patients who need changes in their treatment strategies to prevent progression to invasive disease. Despite these promising results, it is obvious that to increase not only the positive predictive value but especially the negative predictive value of this procedure to predict progression, additional prognostic markers are still needed.     

Intravesical BCG therapy for superficial bladder cancer

Intravesical instillation of Tokyo 172 strain bacillus Calmette-Guerin (BCG) after transurethral resection of bladder tumor (TUR-Bt) was applied to 35 patients with superficial bladder cancer. The patients received 80 mg of BCG in 40 ml saline infused into the bladder once a week for 6 weeks. Actuarial non-recurrence rates for all 35 patients were 81.7% and 58.4% at one and two years after the BCG therapy, respectively. The recurrence of the bladder cancer after the BCG therapy was observed in 12 patients 3-27 months later. Seven patients received an additional course of BCG instillation, and 6 (86%) showed no further recurrence. Thus, the overall success rate of 2 cycles of BCG instillation was 83% (29 of 35 patients). Moreover, in some cases intravesical BCG instillation was effective for recurrent superficial bladder cancer after intravesical instillation of anti-cancer agents and prolonged the period until recurrence. The progression rate was only 5% (2 of 35 patients). These results suggest that intravesical BCG therapy for superficial bladder cancer helps prevent disease progression.     

Altered retinoblastoma protein expression in nonsmall cell lung cancer: its synergistic effects with altered ras and p53 protein status on prognosis

BACKGROUND: Inactivation of the retinoblastoma (Rb) gene has been documented in various types of cancer, including lung cancer. Alterations of the p53 and ras genes are also common features in the molecular biology of lung carcinoma, and the authors of this article have reported previously on the prognostic significance of both of them. In the present study, the authors evaluated the prognostic significance of the loss of Rb protein expression alone, then performed a combined analysis of Rb protein and ras p21 status (Rb/ras) as well as an analysis of Rb and p53 protein status (Rb/p53) in patients with nonsmall cell lung cancer (NSCLC). METHODS: Ninety-one patients with NSCLC underwent potentially curative resection between 1977 and 1988, 65 of whom received postoperative combination chemotherapy. Tumor specimens were analyzed for Rb protein expression by immunohistochemistry. Univariate and multivariate analyses were performed to assess the association between Rb protein expression and survival. RESULTS: Nineteen (21%) of the 91 NSCLCs showed negative Rb protein expression. Positive or negative Rb protein expression (Rb+ or Rb-) as an individual factor was not statistically correlated with survival or prognosis in this cohort of NSCLC patients, although a tendency among Rb- patients to do worse was observed. The authors then combined the Rb protein status with previously studied results of ras p21 and p53 protein expression in the same tumor specimens, and compared the prognosis between the individuals with theoretically the best pattern of gene expression in their tumors and those with theoretically the worst pattern of expression, i.e., Rb+/ras- versus Rb-/ras+ and Rb+/p53- versus Rb-/p53+. In patients with adenocarcinoma, those with Rb-/ras+ tumors survived for a significantly shorter period after surgery (13% 5-year survival) than those with Rb+/ras- tumors (82% 5-year survival) (P = 0.01). Similarly, patients with Rb-/p53+ tumors survived for a significantly shorter period (20% 5-year survival) compared with those who had Rb+/p53- tumors (73% 5-year survival) (P = 0.008). Rb/ras status was a significant prognostic factor (P = 0.02 by univariate analysis, P = 0.048 by multivariate analysis), and Rb/p53 status tended to be significant as a prognostic factor (P = 0.04 by univariate analysis, P = 0.08 by multivariate analysis). In patients with squamous cell carcinoma, neither Rb/ras nor Rb/p53 status was a significant prognostic factor in this cohort. CONCLUSIONS: These results suggest that combined immunohistochemical analyses of Rb and ras p21 proteins and of Rb and p53 proteins may indicate their potentially synergistic effects on survival and prognosis. These analyses may also be useful for stratifying patients with adenocarcinoma of the lung into different prognostic groups and identifying populations with different risks of recurrence. Larger prospective studies with Stage I NSCLC patients are necessary to confirm the current findings.     

Cooperative effects of p53 and pRB alterations in primary superficial bladder tumors

Altered patterns of p53 and pRB expression have been reported to be frequent events and to have prognostic significance in bladder cancer. To assess the potential adverse consequences of having altered patterns of both p53 and pRB proteins in patients with bladder neoplasms compared with having one or neither abnormality, we have studied a cohort of superficial transitional cell carcinomas of the urinary bladder by immunohistochemical analysis. The present study included 59 well-characterized superficial transitional cell carcinomas (Ta, n = 28; T1, n = 31) for which clinicopathological variables were available. Nuclear overexpression of p53 was identified in 22 cases (37%). A statistically significant association was observed between the p53-positive phenotype and disease progression (P < 0.001), as well as reduced survival (P < 0.001). Undetectable levels of pRB were observed in 11 cases (19%). Patients with a pRB-negative phenotype had a more frequent disease progression (P = 0.014) and decreased overall survival (P = 0.014). We also observed a significant association between altered p53 and undetectable pRB expression patterns (P = 0.001). Nine tumors showed both a p53-positive and a pRB-negative phenotype. There was an even more marked increase in progression (P = 0.00005) and decreased overall survival (P = 0.0004) in patients whose tumors had both alterations after controlling for tumor stage, tumor grade, and suspicion of vascular invasion. These data suggest that alterations of p53 and pRB have a cooperative negative effect on both progression and survival in primary bladder cancer. It may be postulated that aberrant p53 and pRB expression deregulates cell cycle control at the G1 checkpoint and engenders tumor cells with reduced response to programmed cell death. The imbalance produced by an enhanced proliferative activity and a decreased apoptotic rate may determine the aggressive clinical course of the bladder tumors harboring both p53 and pRB alterations.     

Clinical implication of screening p53 gene mutations in head and neck squamous cell carcinomas

The role of the tumour-suppressor gene p53 in the tumorigenesis of head and neck cancer has been well established, but the clinical significance of p53 alteration is still unclear. A group of 50 patients with head and neck squamous cell carcinoma (HNSCC) were investigated for p53 alterations. DNA was extracted from fresh tumour samples and polymerase chain reaction/single-strand conformation polymorphism analysis was used to detect p53 gene mutations in the region from exon 5 to exon 9. In addition, p53 protein overexpression was assessed by immunohistochemistry using the monoclonal antibody DO-7 on paraffin-embedded tissue sections. p53 gene mutations were found in 45% and p53 protein expression was detected in 61.2% of tumour samples. While p53 protein expression was not correlated with any clinical factors, p53 gene mutations indicated local regional recurrences of HNSCC. The risk of locoregional recurrence was significantly greater in patients with a p53 gene mutation than in patients with the wild-type p53 gene (P = 0.001). Multivariate analysis confirmed p53 gene mutation to be an independently predictive factor for the tumour recurrence (P = 0.0064). When we analysed p53 gene mutation in 12 patients with primary and recurrent tumours, we found that 4 patients (33.3%) had a different p53 gene mutation in the recurrent tumour from that in the original primary tumour. The results indicate that p53 gene mutations and not protein overexpression are valuable predictors for tumour recurrences and for differential diagnosis of a second primary HNSCC.     

The fate of patients with locally advanced bladder cancer treated conservatively with neoadjuvant chemotherapy, extensive transurethral resection and radiotherapy: 10-year experience

PURPOSE: We assess the results of bladder preservation for infiltrating bladder cancer. The potential for neoadjuvant chemotherapy followed by extensive transurethral resection and radiotherapy was evaluated in 40 patients with T2-T4a G2-G3 bladder carcinoma. MATERIALS AND METHODS: From 1983 to 1995, 40 patients with bladder cancer underwent bladder sparing treatment, consisting of neoadjuvant chemotherapy, extensive transurethral resection and radiotherapy. Most patients had T3G3 cancer. A deep transurethral resection biopsy was performed before and after chemotherapy, and an extensive transurethral resection was repeated at the end of radiotherapy. Of the patients 30 received cisplatin and methotrexate and 10 also received vinblastine. Total dose of radiotherapy was 60 to 65 Gy. Recurrent superficial tumors were treated transurethrally. Radical cystectomy was considered for persistent or recurrent invasive disease. RESULTS: Complete response occurred in 19 patients (47.5%) after chemotherapy, and in 8 patients after transurethral resection and radiotherapy (67.5%). Within 10 years 8 responding patients (30%) had local recurrences and 3 underwent cystectomy. Of the patients 14 (35%) are alive, including 13 with no evidence of disease (mean survival 65 months), 5 died of unrelated disease and 21 (52.5%) died of distant metastases (mean survival 28 months). Of the 21 patients 14 had residual tumor after radiotherapy, 3 presented with distant metastases after vesical infiltrating recurrence and 4 had distant metastases in the absence of locoregional recurrence. In 22 patients (55%) the bladder was salvaged. Patients with complete response to chemotherapy had a low risk for recurrent infiltrating tumors and metastases. CONCLUSIONS: Complete tumor control was maintained at 5 years in more than 50% of the patients treated conservatively. Bladder salvage is feasible in select patients.     

Results of a randomized phase III trial of sequential intravesical therapy with mitomycin C and bacillus Calmette-Guerin versus mitomycin C alone in patients with superficial bladder cancer

PURPOSE: We study toxicity and efficacy of sequential intravesical therapy with mitomycin C and bacillus Calmette-Guerin (BCG) in patients with intermediate or high risk superficial bladder cancer compared to the use of intravesical mitomycin C alone. MATERIALS AND METHODS: Patients with intermediate and high risk papillary superficial bladder cancer and carcinoma in situ were randomized after transurethral resection between 4 weekly instillations with 40 mg. mitomycin C followed by 6 weekly instillations with BCG (group 1, 90 patients) or 10 weekly instillations with mitomycin C (group 2, 92 patients). RESULTS: The frequency of bacterial and chemical cystitis, and other local side effects was similar in both groups. Allergic reactions, including skin rash, were more frequent in the mitomycin C only group (12 of 92 patients versus 5 of 90, p = 0.08), and other systemic side effects were more frequent in the sequential group (16 of 90 versus 8 of 92, p = 0.07). After a median followup of 32 months the number of recurrences (sequential 35 of 90 patients versus mitomycin C only 42 of 92, p = 0.36) and progression (5 of 90 versus 4 of 92 respectively, p = 0.70) were similar in both groups. CONCLUSIONS: We did not find any major differences in toxicity or treatment efficacy with intravesical mitomycin C and the sequential use of BCG or mitomycin C for intermediate and high risk superficial papillary bladder cancer.     

Predicting prognosis in patients with superficial bladder cancer

Bladder cancer is the most common urologic malignancy and is expected to affect approximately 54,000 people in 1998. Superficial bladder tumors (Tis, Ta, and T1 lesions) account for approximately 70% to 80% of these malignancies. Although many advances have been made in the management of patients with superficial bladder cancer, such disease often recurs and can progress, leading to death. It is therefore imperative to find an accurate method of identifying patients at risk for disease progression. Many recent investigations have been conducted to determine whether new biological markers will help predict disease progression and, to a lesser extent, tumor response to treatment. These new markers include DNA ploidy, S-phase, certain monoclonal antibodies, the p53 (alias TP53) tumor-suppressor gene, the retinoblastoma (Rb) gene, cell adhesion molecules, and angiogenesis. It is hoped that such prognostic indicators, coupled with cytoscopic and pathologic characteristics of the tumor, will lead to selective aggressive treatment of patients at high risk for progression while sparing low-risk patients from unnecessary procedures.     

Nerve agent poisoning in primates: antilethal, anti-epileptic and neuroprotective effects of GK-11

Point mutations at the tumour suppressor gene p53 are one of the most frequent genetic alterations in squamous cell carcinoma of the head and neck (SCCHN), which lead to the nuclear accumulation and overexpression of inactive p53 protein. The overexpression of mutant p53 protein can induce a specific humoral response in cancer patients. p53 protein was studied in 112 SCCHN. Biopsies and sera samples were collected before initiation of treatment. 74 patients received neoadjuvant chemotherapy (5-fluorouracil-cisplatin-folinic acid). p53 protein expression was evaluated by immunohistochemistry (IHC) on paraffin-embedded sections. The analysis of mutations was assessed by PCR-SSCP of exons 5-10 on DNA from 28 representative cases. Antibodies specific for p53 protein were analysed in sera of 74 patients by an ELISA procedure. Overexpression (> 20% positive cells) of p53 protein was frequent (56%: 63/112) and was correlated with localisation of the primary tumour and tumour stage. p53 mutations were detected in 57% (16/28) of studied cases. The prevalence of p53 antibodies in sera was high (44% 32/74) and among this population, 68% (20/29) had a positive immunophenotype and 67% (6/9) a p53 mutation in the tumour. In addition, the presence of anti-p53 antibodies was slightly associated with complete response to neoadjuvant chemotherapy. If the humoral response seems to be an indicator of the p53 protein status, the detection of anti-p53 antibodies could be a good approach in the early detection of the presence of p53 alterations in SCCHN and recurrent tumours or the appearance of second primary cancer.     

Expressions of cell cycle regulators in human colorectal cancer cell lines

To study the altered mechanisms of cell cycle regulation in colorectal cancer, the expressions of cyclins, cyclin-dependent kinases (CDKs), CDK inhibitors, p53 and retinoblastoma (Rb) protein were analyzed by western blotting in a series of human colorectal cancer cell lines. The colorectal cancer cell lines exhibited various expression patterns of cell cycle regulators, which may reflect differences in the biological characteristics of cancer cells and in the genetic backgrounds of carcinogenesis. A correlation was found between p53 gene alteration and p21 expression, suggesting that p53 gene mutation usually suppresses p21 expression, though p21 expression could be induced via both a p53-dependent and a p53-independent pathway in colorectal cancer. None of the cell lines studied expressed p16 protein, suggesting that inactivation of p16 may be a common alteration in colorectal cancer. Moreover, all the D-type cyclins, especially D2 and D3, were expressed at a high level in most of the cell lines. Loss of p16 expression and increased expression of D-type cyclins promote CDK-mediated Rb phosphorylation. All of the colorectal cancer cell lines studied herein expressed Rb protein, but the growth-suppressive properties of Rb may be inactivated by the loss of p16 expression and increased expressions of D-type cyclins. In view of the pivotal role of Rb in cell cycle regulation, loss of p16 expression and overexpression of D-type cyclins may be critical alterations in colorectal cancer.     

Molecular screening of multifocal transitional cell carcinoma of the bladder using p53 mutations as biomarkers

Thirteen of 28 patients (46%) with grade 2-3 multifocal transitional cell carcinoma (TCC) of the bladder were found to have p53 mutations using DNA sequence analysis. These were subsequently utilized as tumor-specific biomarkers. Analysis of 17 episodes of recurrence from five of the patients revealed that all but one carried the identical mutation to the primary tumor. Thirty urine samples were collected, at initial diagnosis and during follow-up screening, from eight patients with mutations over a period of 24 months. Sequence analysis of PCR products generated from DNA extracted from the urine sediments was carried out. The p53 mutation seen in the primary tumors was detectable in 24 of 30 urine samples. The remaining six cases coincided with a negative cystoscopic examination. Interestingly, 6 of the 24 urine samples in which mutations were detectable also coincided with negative cystoscopy. The results are consistent with: (a) monoclonality of multifocal TCC; (b) the spread of TCC through a seeding mechanism; and (c) the long-term persistence of tumor cell clones (up to 97 months) within the bladder, even in the absence of obvious tumor growth.     

Ki-67 and p53 in T2 laryngeal cancer

OBJECTIVE: To study the relationship between the proliferative capacity, represented by the immunohistochemical labeling index (LI) of proliferation marker Ki-67, and the p53 status, as in theory an intact p53 cell cycle checkpoint system should result in a lower proliferative capacity. STUDY DESIGN: From a group of 128 patients with a T2 laryngeal carcinoma, presented from 1989 to 1993 at the University Hospital Utrecht, 20 patients with recurrent disease and 16 patients without recurrent disease were randomly selected. All patients received primary irradiation. METHODS: Denaturing gradient gel electrophoresis and immunohistochemistry determined the p53 status. MIB-1 staining was used to determine the Ki-67 LI. RESULTS: In 36% of specimens we found a p53 mutation with overexpression (LI, 31%). In 8% a p53 mutation without p53 overexpression was found (LI, 18%). Forty-two percent showed no mutation but, nevertheless, overexpression (LI, 35%). Neither mutation nor overexpression was found in 14% (LI, 38%). No correlation exists between p53 status and proliferative capacity of tumors (analysis of variance [ANOVA]; P = .104). The proliferation rate as established with Ki-67 LI positively correlates with response to radiotherapy (P = .006). CONCLUSIONS: 1. Overexpression of wild-type p53 protein does not result in cell cycle arrest measurable by a lower Ki-67 LI in comparison with cases overexpressing mutant type p53 protein. 2. A high Ki-67 LI correlates with a favorable response to radiotherapy.     

p53 status does not predict initial clinical response to bacillus Calmette-Guerin intravesical therapy in T1 bladder tumors

PURPOSE: In superficial urothelial tumors of the bladder, p53 status is currently the most informative pretreatment parameter to define a population at higher risk for invasive carcinoma. Also, in T1 tumors, occurrence of muscular invasion is often related to an early relapse following BCG therapy. With the knowledge of biological parameters able to identify the group of initial BCG therapy non-responders, it would be possible to offer earlier treatment to the patients who need a more aggressive mode of therapy. The aim of this work was to study the predictive value of the p53 tumor status on the early BCG therapy response. MATERIALS AND METHODS: The population included a selected group of 43 patients presenting T1 bladder tumors with no carcinoma in situ (Tis), treated by transurethral resection (TUR) followed by intravesical BCG therapy. Clinical outcome was analyzed in relation to usual clinical and histopathological parameters, and pretreatment p53 tumor status was assayed by an immunohistochemical technique using DO7 monoclonal antibody. For 16 specimens, p53 gene was investigated using a Single Strand Conformation Polymorphism (SSCP) analysis and sequence determination. RESULTS: p53 anomalies were strongly correlated to smoking behavior (p = 0.003) and tumoral grade (p = 0.025). Univariate analysis revealed an absence of correlation between p53 immunostaining and initial, one and two years response-rate to BCG therapy. However, longterm followup revealed a trend between positive staining and disease progression. The p53 molecular study validated the use of DO7 immunostaining in detection of p53 anomalies. CONCLUSIONS: In T1 bladder tumors, pretreatment p53 determination was not useful to define a group of early BCG non-responders. Thus, p53 status and immunological response induced by BCG endovesical therapy are two independent events.     

Isolation and characterization of a novel bladder cancer cell line: inhibition by epidermal growth factor

A novel continuous cell line, designated BC3c, was established from a surgical biopsy of an invasive solid transitional cell carcinoma of the bladder derived from an 82-yr-old Caucasian female. BC3c cells were near-triploid bearing multiple structural and numerical chromosome anomalies. The epithelial origin of the cancer cells was indicated by the expression of cytokeratins 8 and 19 as well as by the absence of mesenchymal markers. Polymerase chain reaction-restriction-fragment length polymorphisms and single-strand conformation polymorphism mutation detection assays did not reveal any mutations in H-ras codon 12 and K-ras codons 12 and 13. In addition, no mutation in specific hot-spot codons of the p53 gene and no accumulation of the p53 protein were observed. BC3c cells grew rapidly in vitro, even in the absence of exogenous growth factors, because they were found to stimulate their growth in an autocrine manner. BC3c cells were found to express the epidermal growth factor-receptor (EGF-r) abundantly, but in contrast to other established bladder cancer cell lines, human recombinant epidermal growth factor inhibited the cells' proliferation in vitro. These features render the newly established bladder cancer cell line BC3c a useful tool for further experimentation.     

Selective bladder preservation by combination treatment of invasive bladder cancer

BACKGROUND: For patients with invasive bladder cancer the usual recommended treatment is radical cystectomy, although transurethral resection of the tumor, systemic chemotherapy, and radiotherapy are each effective in some patients. We sought to determine whether these treatments in combination might be as effective as radical cystectomy and thus might allow the bladder to be preserved and the cancer cured. METHODS: We enrolled 53 consecutive patients with muscle-invading bladder cancer (stages T2 through T4, NXM0) in a trial of transurethral surgery, combination chemotherapy, and irradiation (4000 cGy) with concurrent cisplatin administration. Urologic evaluation of the tumor response directed further therapy: radical cystectomy in the 8 patients who had incomplete responses, additional chemotherapy and radiotherapy (6480 cGy) in the 34 patients who had complete responses or who were unsuited for cystectomy, and alternative care in the 11 patients who could not tolerate either irradiation or chemotherapy. RESULTS: After a median follow-up of 48 months, 24 of the 53 patients (45 percent) were alive and free of detectable tumor. In 31 patients (58 percent) the bladder was free of invasive tumor and functioning well, even though in 9 (17 percent) a superficial tumor recurred and required further transurethral surgery and intravesical drug therapy. Of the 28 patients who had complete responses after initial treatment, 89 percent had functioning tumor-free bladders. CONCLUSIONS: Conservative combination treatment may be an acceptable alternative to immediate cystectomy in selected patients with bladder cancer, although a randomized clinical trial that included a group for simultaneous comparison would be required to produce definitive results.     

An uncertain role for p53 gene alterations in human prostate cancers

Inactivation of the p53 gene has been implicated in prostate cancer progression. To determine the role of p53 inactivation in the progression of clinical prostatic carcinomas, we assessed 67 tumors derived from patients with clinically localized disease for chromosome 17p and p53 gene allelic loss, p53 gene mutations using single-strand conformational polymorphism and direct sequencing, and p53 protein expression using immunohistochemical staining. Of 55 informative tumors, 10 demonstrated loss of 17p or the p53 gene; however, only a single tumor had a mutation in its remaining p53 allele. Significant p53 overexpression was observed in 2 of 38 tumors, and 9 others had faint staining of a few nuclei ( < 1%). p53 overexpression occurred in no informative tumor with allelic loss or mutation. In a 1-7-year follow-up, positive immunohistochemical staining did not confer an increased risk of recurrence (risk of recurrence, 0.86, P = 0.78), whereas allelic loss of chromosome 17p appeared to be highly correlated with recurrence (risk of recurrence, 3.7, P = 0.003). In an unrelated group of 42 patients with metastatic prostate cancer, p53 overexpression was found in 26 tumors (62%), and 15(36%) had high grade staining. Neither the presence nor the degree of expression correlated with time to progression or time to death. This series suggests that p53 gene inactivation is rare in primary prostatic tumors, not essential to the development of prostate cancer metastases, and of limited use as a prognostic marker in patients with primary or metastatic disease. Another gene or genes on chromosome 17p may be involved in prostate cancer progression.     

Transforming growth factor-beta receptors on human endometrial cells: identification of the type I, II, and III receptors and glycosyl-phosphatidylinositol anchored TGF-beta binding proteins

BACKGROUND: Mutation of the p53 tumor suppressor gene is the most commonly found genetic alteration in human cancer. The E6 gene product of human papillomavirus (HPV) 16 and 18 can inactivate the p53 protein by promoting its degradation. Because most HPV-positive cervical carcinoma cell lines contain wild-type p53 whereas HPV-negative cell lines have point mutations in the p53 gene, a major role in the development of HPV-negative cervical cancer has been attributed to p53. Recent studies, however, have observed no consistent presence of p53 mutation in HPV-negative primary cervical carcinomas. The MDM2 oncogene, which forms an autoregulatory loop with the wild-type p53 protein, has been found amplified in a high percentage of human sarcomas, thus abolishing the antiproliferative function of p53. METHODS: Forty-three primary cervical carcinomas and 10 autopsy-derived distant metastases from one patient were examined for p53 mutation and MDM2 amplification. These tumors had been selected from 238 cervical cancers that had been HPV-typed by Southern blot hybridization and polymerase chain reaction as a representative sample for their HPV status and their clinicopathologic characteristics. Seventeen of the cases had a remarkably good or poor clinical outcome. Human papillomavirus DNA sequences had been detected in 30 of these 43 primary tumors and 13 were negative for HPV by both methods. p53 mutation in the highly conserved exons 5-8 was studied by single-strand conformation polymorphism analysis and direct sequencing. MDM2 amplification was analyzed by Southern blot hybridization. RESULTS: Only two missense point mutations and one nucleotide sequence polymorphism were detected: a TAC-->TGC transition in codon 234 in exon 7, resulting in a Tyr-->Lys substitution, a CGT-->TGT transition in codon 273 in exon 8, resulting in an Arg-->Cys substitution and a polymorphism (CGA-->CGG) in codon 213 in exon 6. Both tumors revealing the point mutations were HPV-negative carcinomas. Amplification of the MDM2 gene was observed in 1 of the 53 specimens tested. CONCLUSIONS: In contrast to data derived from cultured cervical carcinoma cell lines and primary sarcomas, these results indicate that p53 mutation and amplification of the MDM2 oncogene are rare even in HPV-negative primary cervical carcinomas. However, to the authors; knowledge, this is the first observation of MDM2 amplification in humans outside sarcomas and neuroepithelial tumors.     

Molecular pathologic substaging in 244 stage I non-small-cell lung cancer patients: clinical implications

PURPOSE: To retrospectively construct a comprehensive multivariate model of cancer recurrence and to design a molecular pathologic substaging system in stage I non-small-cell lung cancer (NSCLC). METHODS: All patients with stage I NSCLC resected at Brigham and Women's Hospital (Boston, MA) between 1984 and 1992 with adequate clinical follow-up were studied. The importance of three demographic characteristics, surgical extent, 11 pathologic features, and seven molecular factors on cancer-free survival was examined. RESULTS: Two hundred forty-four patients were studied, with 25 noncancer deaths and 80 patients with recurrent disease. Significant univariate predictors (P < .05) of cancer recurrence were age older than 60 years, male sex, wedge resection, World Health Organization (WHO) adenocarcinoma subtype solid tumor with mucin, lymphatic invasion, and p53 expression. Multivariate analysis identified nine independent predictors of recurrence: solid tumor with mucin, a wedge resection, tumor diameter of 4 cm or greater, lymphatic invasion, age older than 60 years, male sex, p53 expression, K-ras codon 12 mutation, and absence of H-ras p21 expression. Multivariate cancer-free survival (CFS) analysis in the 180 patients who underwent lobectomy or pneumonectomy led to the elimination of sex and age, which left six independent factors. CONCLUSION: Lobectomy or pneumonectomy should be performed in stage I NSCLC. Using the six independent factors for recurrent disease, we propose a pathologic molecular substaging system. Patients with two factors or less are graded Ia, with a 5-year CFS rate of 87%; those with three factors are graded Ib, with a 5-year CFS rate of 58%; and those with four factors or more are graded Ic, with a 5-year CFS rate of 21%.