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.     

Expression of the tumor suppressor gene p53 in superficial transitional carcinoma of the bladder

Presentation of 113 cases of transitional cells surface tumours of the bladder where p53 protein expression has been used and compared to known prognostic factors. The existence of a statistically significant relationship between this expression and the tumoral grade and stage in all studied groups has been noticed. It can be concluded that the expression of this protein can be useful as a new prognostic factor, even though it is still necessary to conduct more studies, basically prospective.     

Analysis of p21WAF1/CIP1 in primary bladder tumors

The p21WAF1/CIP1 gene is regulated by p53 and encodes a cyclin-dependent kinase (Cdk)-inhibitor involved in senescence and cell quiescence. The role of p21 as a negative regulator of cell proliferation suggests that it may function as a tumor suppressor gene. However, only a few mutations of the p21WAF1/CIP1 gene have been reported to date. In order to assess potential p21WAF1/CIP1 gene alterations in human bladder cancer, we have examined this gene and its encoded product in a well-characterized cohort of 27 primary bladder tumors. Mobility shifts by single-strand conformation polymorphism in the p21WAF1/CIP1 gene were identified in 2 cases. Sequencing analyses revealed that one of these cases had point mutations in the 3' untranslated region, while the other case had a frame shift mutation at positions 322 (C to A) and a deletion of 8 nucleotides (323-->331; CCG-->ACG, codon 81 Arg-->Thr) that produced a stop signal at codon 83 (Gly--Stop). This tumor had a p21-negative phenotype by immunohistochemistry, but did not lose any allele. We further characterized these cases by the study of TP53 mutations using single-strand conformation polymorphism (PCR-SSCP) and sequencing, as well as immunohistochemical assays. Seven mobility shifts were identified and seven cases showed p53 nuclear accumulation. The two cases displaying mutated p21WAF1/CIP1 had wild-type TP53. It is concluded that p21WAF1/CIP1 gene aberrations are infrequent in bladder carcinoma but may be occasionally identified in primary bladder tumors.     

Clinicopathologic implications of MDM2, p53 and K-ras gene alterations in osteosarcomas: MDM2 amplification and p53 mutations found in progressive tumors

The role of rapidly growing mycobacteria in the pathogenesis of pulmonary disease is being increasingly recognized; however, the clinical significance of these mycobacteria in patients with underlying malignancy has not been well studied. Over a 6-year period, 37 cancer patients with rapidly growing mycobacteria isolated from respiratory specimens were identified at our center. Mycobacterium chelonae group was isolated in 24 cases and Mycobacterium fortuitum in 13 cases. Of the 24 cases with cultures yielding Mycobacterium chelonae group, eight met the study criteria for infection and were determined to be clinically significant, whereas only one of the Mycobacterium fortuitum isolates was determined to represent infection. An average of two antimicrobial agents were used for treatment, most commonly clarithromycin, ciprofloxacin, and trimethoprim/sulfamethoxazole. Although the isolation of rapidly growing mycobacteria represents colonization in most cases, these bacteria, especially the Mycobacterium chelonae group, may cause pulmonary disease in cancer patients. The clinical and radiological findings are usually non-specific in this population, and patients with respiratory cultures yielding rapidly growing mycobacteria should be assessed carefully to distinguish infection from colonization. Effective therapy can be provided with oral regimens that include at least two antibiotics to which the organism is susceptible.     

p53 mutagenesis in Klatskin tumors

Mutagenesis of the p53 tumor-suppressor gene represents the most common genetic alteration in human malignancies but has not yet been investigated in Klatskin tumors. Cancerous and normal liver tissues were obtained from 12 patients after surgical resection of Klatsin tumors. Genomic DNA was extracted and served as a template for PCR amplification and sequencing of a 1,574-bp fragment of the p53 gene comprising the exons 5 through 8. Immunohistochemical expression analysis was performed using five different antibodies. Missense mutations were detected in 2 of 12 patients--one transversion on codon 273 (Arg --> Leu) and a transition on codon 168 (His --> Arg). In all specimens, immunohistochemistry was negative regarding a nuclear overexpression. An apparent clinicopathologic impact of p53 mutations was not observed. This report on mutagenesis of the p53 gene in Klatskin tumors shows that the most commonly mutated tumor suppressor gene in human cancers is also mutated in a subset of patients with Klatskin tumors. Assessment of a clinical or pathological impact of p53 mutagenesis on Klatskin tumors requires evaluation in larger studies.     

The prognostic importance of the immunohistochemical study of protein p53 in transitional-cell bladder tumors

In an immunohistochemical investigation designed to study a mutated p53 protein in transitional-cell tumours (n = 44) we succeeded in identifying the presence of two types of transitional-cell tumours of human urinary bladder, such as p53 immunopositive and p53 immunonegative transitional-cell tumours. Thus, the results of the immunohistochemical investigation into the protein p53 were found out to directly correlate with the clinical course of transitional-cell tumours, that are held to be of great differential-diagnostic and prognostic significance.     

Recombinant tumor necrosis factor for superficial bladder tumors

Twenty patients with histologically documented superficial bladder cancer (Ta, T1, Tis) were treated with intravesical administration of TNF 400-1800 micrograms. Of 18 patients with a marker lesion, 2 obtained a complete response for 8+ and 18 months. Two had a partial response and were given other intravesical therapies after 5 and 7 months. No or minimal systemic absorption of TNF was observed and documented in 4 of 20 patients by pharmacokinetic studies, and no patients developed antibodies to intravesically administered TNF. TNF was well tolerated in doses up to 1800 micrograms. No systemic or local side effects were observed. Modest activity was attained with intravesical TNF, even in pretreated patients.     

Expectant treatment of superficial bladder tumors: preliminary results]

A group of patients presenting with superficial bladder tumors (Ta-T1, G1-G3) was entered in a surveillance program following TUR. A standard univariative analysis was used to study tumor and patient prognostic factors to recurrence and progression. To define further the importance of each variable, a multivariative analysis was performed. Regardless of stage, grade and sex, patients with multiple tumors and/or size > or = 2 cm were particularly exposed to frequent recurrences. Early recurrences (before month 9) were associated with high recurrence rates. Considering the results of topical chemotherapy and toxicity of BCG immunotherapy, surveillance could be and option for superficial bladder tumors, reserving adjuvant therapy for large, multiple or early recurrence.     

Circulating p53 antibodies as early markers of oral cancer: correlation with p53 alterations

p53 aberrations are early events in the pathogenesis of betel- and tobacco-related oral malignancies. Accumulation of p53 protein in oral lesions may elicit a humoral immune response against p53 protein in these patients. p53 antibodies (Abs) were analyzed in 183 sera obtained from patients with premalignant or malignant oral lesions and normal individuals by enzyme-linked immunoassay using recombinant p53 protein as antigen. These results were correlated with accumulation of p53 protein in patients' matched oral tissue specimens. Circulating p53 Abs were observed in 24 of 70 (34%) cancer patients and 15 of 50 (30%) patients with premalignant oral lesions. p53 Abs showed a significant association with increase in tumor size and dedifferentiation of tumors, factors indicative of poor prognosis. Expression of p53 protein was analyzed in 43 matched oral lesions (18 premalignant and 25 malignant cases). All the p53-seropositive patients (7 leukoplakia and 11 squamous cell carcinoma) showed elevated levels of p53 protein in matched oral lesions. However, the total number of patients seropositive for p53 Abs was lesser than that of patients exhibiting p53 protein accumulation in oral lesions. Four of the 63 normal healthy individuals who were heavy consumers of tobacco (smoking/chewing) and betel were found to be positive for p53 Abs. Detection of circulating p53 Abs in patients with premalignant oral lesions suggests that humoral immune response against p53 protein is an early event in oral oncogenesis and may be a surrogate marker for both p53 alteration and preclinical cancer.     

Retention of wild-type p53 in tumors from p53 heterozygous mice: reduction of p53 dosage can promote cancer formation

Tumor suppressor genes are generally viewed as being recessive at the cellular level, so that mutation or loss of both tumor suppressor alleles is a prerequisite for tumor formation. The tumor suppressor gene, p53, is mutated in approximately 50% of human sporadic cancers and in an inherited cancer predisposition (Li-Fraumeni syndrome). We have analyzed the status of the wild-type p53 allele in tumors taken from p53-deficient heterozygous (p53+/-) mice. These mice inherit a single null p53 allele and develop tumors much earlier than those mice with two functional copies of wild-type p53. We present evidence that a high proportion of the tumors from the p53+/- mice retain an intact, functional, wild-type p53 allele. Unlike p53+/- tumors which lose their wild-type allele, the tumors which retain an intact p53 allele express p53 protein that induces apoptosis following gamma-irradiation, activates p21(WAF1/CIP1) and Mdm2 expression, represses PCNA expression (a negatively regulated target of wild-type p53), shows high levels of binding to oligonucleotides containing a wild-type p53 response element and prevents chromosomal instability as measured by comparative genomic hybridization. These results indicate that loss of both p53 alleles is not a prerequisite for tumor formation and that mere reduction in p53 levels may be sufficient to promote tumorigenesis.     

Mutation of p53 gene and genomic instability in testicular tumors

BACKGROUND: During the past decade, studies of human cancer have begun to yield molecular information on the identify of the multiple genetic changes in the development and progression of tumorigenesis. We investigated alterations of p53 and genomic instability in testicular tumors. MATERIALS AND METHODS: Polymerase chain reaction (PCR) single-strand conformation polymorphism was performed for analysis from exons 5 to 8 of p53 gene in 22 cases and PCR-microsatellite instability analysis using 8 microsatellite markers were conducted in 19 cases of testicular tumor. RESULTS: No mutations were noted for exons 5 to 8 of the p53 gene. Differences in unrelated microsatellites for tumor and corresponding normal DNA were detected in 5 of 19 (26.3%) cases examined. Alterations noted in more than 2 microsatellites were observed in 3 of 19 (15.8%) and categorized as replication error (RER) phenotype. Two of 7 (28.6%) seminomatous and 1 of 12 (8.3%) non-seminomatous testicular tumors patients showed RER. Two of 16 (12.5%) stage T1-3N0M0 and 1 of 3 (33.3%) stage T1-3N1-3M0-1 showed RER. CONCLUSIONS: Alterations in microsatellite instability may be involved in the development of testicular tumor.     

Comparative analysis of p53 mutations in bladder washings and histologic specimens

PURPOSE: To analyze and compare the light energy distribution generated by multifocal intraocular lenses (IOLs). SETTING: Laser Laboratory of the Department of Electronics, Electrotechnics and Informatics, University of Trieste, Italy. METHODS: An optic system to examine the division of a laser beam in the various focal spots of multifocal IOLs was developed. The model consists of a helium-neon laser and an optical system: a triangular optical bench with a precision collimator, a micropositionable immersion stage supporting the IOL to be measured, and a digital image-processing system. Four bifocal and three multifocal IOLs were studied. This system is able to expand the distance between foci, leading to a sharper separation of the focal spots. The resolution of the images makes it possible to analyze the distribution of total light energy among the foci. RESULTS: Results showed the variation in light intensity of the focal spots of multifocal and bifocal IOLs, as well as their disposition in the dioptric range. CONCLUSION: Light distribution among various focal distances corresponded to the foci provided by monofocal, bifocal, and multifocal IOLs. The percentage of light energy distribution was related to the importance of each focus.     

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.     

Evaluation of c-ras oncogene product (p21) in superficial bladder cancer

OBJECTIVES: The aim of our study is the evaluation of the prognostic importance of p21 protein in superficial bladder cancer. METHODS: One hundred and fourteen patients with an initial diagnosis of monofocal bladder cancer (stage Ta-T1) following TUR were investigated. On the tissue removed by TUR, besides the usual pathological evaluation, an immuno-histochemical investigation was carried out in order to ascertain the presence of c-ras oncogene product (protein p21). The actuarial curves concerning the time free from the first recurrence were computed, comparing different subgroups in regard to protein p21 presence, grade and stage of the tumour. RESULTS: The analysis of the results shows the importance of tumour stage as a predictor of recurrence, as well as that of the presence of c-ras products. This last factor increases the risk of recurrence almost 2-fold, in the same time lag, for c-ras-positive patients (p < 0.001). The prognostic significance of c-ras is independent of stage. CONCLUSION: Our data underline the possibility of acquiring important information on the prognosis of superficial bladder cancer patients, pointing out the significance of c-ras oncogene product.     

p53 alterations are associated with improved prognosis in distal colonic carcinomas

Alterations of the p53 gene and the p53 protein are common in a wide spectrum of human malignancies. In several tumor types, p53 gene mutation and/or p53 protein overexpression correlate with a more clinically aggressive phenotype as judged by worse patient survival. This has not been clearly demonstrated to be the case in colorectal cancer. Herein, we report results of the prognostic significance of p53 protein accumulation and gene mutation in a large series of colorectal cancers (n = 541) with long patient follow-up (mean, 87 months). The large majority of patients (95%) received no postoperative systemic adjuvant therapy. The incidence of p53 accumulation detected by immunohistochemistry with the monoclonal antibody DO-7 was 30%, whereas the incidence of p53 gene mutation in exons 5-8 detected using PCR-single strand conformation polymorphism was 36%. Accumulation of p53 protein was associated with improved patient survival independent of tumor stage or grade (hazard ratio, 0.66; 95% confidence interval, 0.47-0.93; P = 0.017). A marked difference was observed depending on the location of the tumor: tumors originating in the distal colon showed a strong association between the presence of p53 accumulation and improved patient survival (P = 0.003), but this was not the case for those located in the proximal colon. Dukes' stage C tumors, but not stage B, also showed an association between p53 accumulation and better outcome (P = 0.013). Mutation of the p53 gene was associated with a trend toward improved survival, particularly in the distal tumors. Our results demonstrate that in some tumor types, the presence of p53 abnormalities can correlate with better prognosis.     

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.