Vimentin expression in different types of breast carcinoma immunohistochemical study

Vimentin was preferentially expressed in medullary and high grade ductal not otherwise specified (NOS) carcinomas. It was not expressed in lobular carcinoma whether of the classical or the variant types. In the present study, 58 cases of invasive breast carcinomas were tested for vimentin on formaldehyde fixed paraffin embedded sections. Vimentin was expressed in 14/ 44 (32%) of infiltrating duct carcinoma NOS. It was expressed in less than 10% of tumour cells in 5/44 (11.4%) and in > or = 10% of tumour cells in 4/7 (57%). However, none of the lobular carcinoma expressed vimentin. Vimentin was expressed in 9 of 18 (50%) of grade III infiltrating duct NOS carcinoma versus 5 of 21 (24%) of grade II and 0 of 5 (0%) of grade I carcinoma. It was preferentially expressed in tumour growing in broad anastomosing bands or sheets with numerous mitoses, high nuclear grade, scanty supportive stroma and extensive necrosis.     

Spindle cell carcinoma of the breast: a case report and an immunohistochemical study including p53 and Ki-67 expression

A rare case of spindle cell carcinoma (SpCC) of the breast occurring in a 51-year-old Japanese woman is reported. A firm and well-circumscribed tumor, measuring 9 x 8.5 x 8.5 cm, was located on the upper lateral region of the right breast. Microscopically, the tumor consisted of sheets of both malignant spindle cells and poorly differentiated ductal carcinoma containing squamoid islands with gradual transition to the spindle cell component. The immunocytochemical expression of epithelial markers was recognized in the spindle cells, as well as in the carcinomatous cells. Moreover, the spindle cell component expressed vimentin, alpha-smooth muscle actin and S-100 protein. Ultrastructurally, in addition to the features of adenocarcinoma, squamous or myoepithelial differentiation was confirmed in the spindle cell component. These findings thus suggest an epithelial origin with squamous differentiation and myoepithelial participation in the genesis of SpCC. In a comparative study, the expression of p53 protein and Ki-67 as a proliferation marker in each component of this tumor was also investigated. The mean p53 labeling index (LI) in both the carcinomatous and spindle cell area was similar, however the mean MIB-1 LI in the spindle cell area was significantly higher than that in the carcinomatous area. The results indicate that p53 overexpression is involved in the tumorigenesis of both components in the SpCC, and the spindle cell component shows a higher degree of proliferative activity than the carcinomatous component.     

p53 in node-negative breast carcinoma: an immunohistochemical study of epidemiologic risk factors, histologic features, and prognosis

PURPOSE: The present study explores p53 in relation to the following four aspects of node-negative breast carcinoma: epidemiologic risk factors, tumor histopathology, prognosis, and HER2/neu (HER) expression. MATERIALS AND METHODS: Immunohistochemical (IH) staining for p53 was performed on formaldehyde-fixed, paraffin-embedded primary invasive carcinomas from 440 node-negative patients with a median follow-up duration of 119 months. RESULTS: The IH expression, or lack thereof, of p53 separately or in combination with HER did not prove to be prognostically significant and there was no consistent association of p53 with epidemiologic risk factors. p53 was expressed in 68% of medullary carcinomas (MEDs), which is a significantly higher frequency (P < .001) than in lobular (9%) and duct (23%) carcinomas. p53 was not found in some types of low-grade carcinomas (tubular and papillary), and was observed in a minority of mucinous carcinomas. p53 was present significantly more often in carcinomas with high-grade or poorly differentiated nuclear grade than in low- or intermediate-grade tumors. There was an inverse statistically significant relationship between estrogen receptor (ER) positivity and p53 expression. Tumors with the p53(+)/HER(-) immunophenotype tended to be MEDs or duct carcinomas with a marked lymphoplasmacytic reaction. Infiltrating lobular carcinomas (IFLCs) were largely p53(-)/HER(-). p53(+)/HER(+) carcinomas had the best prognosis. The poorest outcome was associated with the p53(-)/HER(+) immunophenotype. This trend was statistically significant for recurrence-free and overall survival in patients with T1NOMO infiltrating duct carcinoma (IFDC). CONCLUSION: The IH demonstration of p53 was not a reliable prognostic indicator in the node-negative breast carcinoma patients studied and it was not associated with major epidemiologic risk factors. The combined immunophenotypic expression of p53 and HER was significantly associated with some histologic types of breast carcinoma and with prognosis in T1NOMO breast carcinoma.     

Racial disparity in the association of p53 gene alterations with breast cancer survival

A significant black/white difference in breast cancer prognosis has been observed in the United States. Alterations of p53 tumor suppressor gene in breast cancer have been associated with poor prognosis. This study was designed to test the hypothesis that p53 gene alterations are related to the difference in prognosis between black and white breast cancer patients. Formalin-fixed paraffin-embedded breast tissue blocks were available from 45 black and 47 white patients for PCR-single strand conformation polymorphism analysis and DNA sequencing. The types of p53 gene alterations were compared between blacks and whites. Associations between p53 gene alterations and survival were also evaluated. Three missense, 2 nonsense, 1 microdeletion, 1 intron, and 4 silent mutations were detected in blacks, while 7 missense, 1 microdeletion, 1 silent mutation, and 3 polymorphisms were observed in whites. Among the point mutations, G:C to A:T transitions at non-CpG sites were found in 80.0% of blacks (8 of 10) and 62.5% of whites (5 of 8). Significantly poorer survival associated with p53 gene alterations was observed for blacks (P = 0.012), but not for whites. Black patients with p53 alterations had a significant 4-5-fold excess risk of death from breast cancer than those without p53 alterations. Adjustment for stage, age, tumor histopathology, receptor status, and adjuvant treatment did not change the excess risk. The findings suggest that the types of p53 gene alterations may contribute to the racial difference in breast cancer survival.     

p53 and bcl-2 immunohistochemical alterations in prostate cancer treated with radiation therapy

PURPOSE: Upper urinary tract calculi that are too large to treat with extracorporeal shock wave lithotripsy are most commonly cleared with percutaneous endoscopic techniques. In a select group of patients who were poor candidates for percutaneous nephrostolithotomy we used retrograde endoscopic lithotripsy, and define the safety and efficacy of this modality in treating large, noninfectious stone burdens (2 cm. or greater). MATERIALS AND METHODS: A total of 51 patients with 66 large (2 cm. or greater) upper urinary tract stones were chosen for retrograde ureteroscopic surgery. Many of these patients had co-morbid conditions that precluded or complicated standard percutaneous treatment. Lithotripsy was based on the application of small diameter fiberoptic ureteroscopes and the holmium laser lithotriptor. Specifically, the 200 micro. laser fiber was used when lower pole renal access was required. Successful therapy was defined as total fragmentation of a stone burden with creation of fine sand and 2 mm. or smaller debris. Second look endoscopy was commonly performed in select patients with large branched calculi or stone burdens in excess of 3 cm. to rule out and treat large residual fragments. RESULTS: Of 51 patients 48 were treated solely in a retrograde ureteroscopic manner and in 3 either failure of lower pole access or infectious material encountered on initial endoscopy led to conversion to more standard percutaneous techniques. In 34 of 45 renal (76%), and 20 of 21 ureteral (95%) complete ureteroscopic fragmentation of the respective stone burden was accomplished after a single session. Second look endoscopy defined significant residual fragments requiring additional endoscopic lithotripsy in 8 of 15 large renal (53%) and 1 of 3 complex ureteral stone burdens. Success, that is complete pulverization of the stone burden to fine dust and small 2 mm. fragments, increased to 41 of 45 renal (91%) and all 21 ureteral calculi after these second look procedures. One patient required a third session to treat completely an exceptionally large (6 cm.) renal stone burden composed of pure cystine, thus increasing the overall success rate for renal calculi to 93%. Six-month followup data were available for 25 patients with large calculi treated ureteroscopically, of whom 15 (60%) had completely clear imaging, 6 (24%) had small lower pole debris that was decreasing on serial imaging and 4 (16%) had new stone growth which was, in part, related either to uncorrectable metabolic disorders or chronic renal scarring and urinary stasis. There were no intraoperative complications. Three postoperative complications included pyelonephritis in 1 patient, prostatic bleeding in 1 on anticoagulant therapy and a cerebral vascular accident 24 hours after the procedure in 1 with severe vascular disease. CONCLUSIONS: Large and complex upper urinary tract calculi can be addressed safely and efficiently with retrograde endoscopic techniques.     

p53 tumor-suppressor gene: clues to molecular carcinogenesis

Pig oocytes were examined to test their ability to undergo cortical granule exocytosis upon penetration by spermatozoa during meiotic maturation. Immature or maturing oocytes (cultured in vitro for 0 h, 26 h and 46 h) were inseminated with ejaculated boar spermatozoa in vitro. Before and after insemination, oocytes were stained with peanut agglutinin labelled with fluorescein isothiocyanate and the cortical granule distributions were examined under the fluorescent microscope and the laser confocal microscope. Before insemination, all the oocytes at the germinal vesicle stage showed a uniform distribution of cortical granules throughout the cortical cytoplasm. The granules migrated centrifugally during maturation and were distributed just beneath the oolemma in the oocytes after germinal vesicle breakdown, forming a monolayer in metaphase I or metaphase II. Cortical granules were still present in all penetrated oocytes at the germinal vesicle stage 18 h after insemination; in contrast, 26% and 84% of the oocytes inseminated at the stages of germinal vesicle breakdown or at metaphase I and II, respectively, completely released their cortical granules. Nuclear activation rates of penetrated oocytes were 0%, 38% and 96% in oocytes cultured for 0 h, 26 h and 46 h, respectively. Of the nuclear-activated oocytes, 67% (oocytes cultured for 26 h) and 88% (oocytes cultured for 46 h) released cortical granules completely. Complete cortical granule exocytosis was not observed in nuclear-inactivated oocytes. Of the nuclear-activated oocytes, 67% (oocytes cultured for 26 h) and 80% (oocytes cultured for 46 h) of monospermic oocytes and 67% (oocytes cultured for 26 h) and 91% (oocytes cultured for 46 h) of polyspermic oocytes released cortical granules, and no statistical difference was observed between oocytes cultured for 26 h or 46 h, or between monospermic and polyspermic oocytes. The proportion of oocytes with cortical granule exocytosis increased as insemination time increased and was greatest 18 h after insemination in oocytes cultured for 26 h and 46 h; no obvious changes were observed when the insemination time was prolonged to 24 h. These results indicate that pig oocytes develop the ability to release cortical granules after penetration by spermatozoa following germinal vesicle breakdown, and that this ability is not fully developed until metaphase II. Cortical granule exocytosis is accompanied by nuclear activation, suggesting that both nuclear and cytoplasmic maturation are responsible for the cortical reaction. Polyspermy may be a result of a complete failure of cortical granule exocytosis in immature oocytes and delayed CG exocytosis in matured oocytes.     

Therapeutic usefulness of wild-type p53 gene introduction in a p53-null anaplastic thyroid carcinoma cell line

Anaplastic thyroid carcinomas very often harbor the mutations in the tumor suppressor gene p53. We have previously shown that wild-type (wt) p53 gene introduction led to cell growth arrest, but not apoptosis, in p53-null anaplastic thyroid carcinoma cells. The present studies were designed to evaluate other therapeutic effects of wt-p53 gene introduction on p53-null thyroid carcinoma cells, as chemo- and radiosensitization and inhibition of angiogenesis have also been described recently as additional therapeutic advantages of wt-p53 gene introduction in tumor cells with p53 mutations. A p53-null anaplastic thyroid carcinoma cell line, FRO, and a FRO subline stably expressing a temperature-sensitive (ts) mutant of p53 (p53Val138), tsFRO, were used. ts-p53 functions as mutant and wt at nonpermissive (37 C) and permissive (32 C) temperatures, respectively. tsFRO showed a prolonged cell doubling time compared to parental FRO when cultured at 32 C, but the cell growth rate was similar between FRO and tsFRO at 37 C. The cytotoxic and clonogenic assays demonstrated that although the sensitivity to three different anticancer agents (cisplatin, 5-fluorocytosine, and doxorubicin) was unaltered, radiosensitivity was enhanced in tsFRO compared to FRO at 32 C. Unexpectedly, in studies on angiogenesis, expression levels of vascular endothelial growth factor (an angiogenic factor) messenger ribonucleic acid were similar between FRO and tsFRO, and thrombospondin-1 (an antiangiogenic factor) messenger ribonucleic acid and protein levels were about 2.5-fold lower in tsFRO than FRO at 32 C, although any difference could not be detected in their ability to inhibit in vitro angiogenesis with the culture medium conditioned by tsFRO and FRO at 32 C. These results suggest that p53-defective thyroid carcinomas may benefit from the combination of p53 gene therapy and radiotherapy. However, further study will be necessary to clarify the pathological significance of thrombospondin-1 in angiogenesis and thyroid tumor growth.     

Correlation between p53 mutations and antibody staining in breast carcinoma

Abnormalities of the p53 gene and protein were examined in 81 primary breast carcinoma samples. Using a polymerase chain reaction-single-strand conformational polymorphism (PCR-SSCP) analysis, mutations in p53 exons 5-8 were identified in 13 of 81 tumours (16 per cent) and confirmed by DNA sequencing. Positive staining for p53 protein was detected in ten of 77 (13 per cent) of these tumours using polyclonal CM1 antibody on formalin-fixed tissue. Mutations detected by PCR-SSCP analysis were more common in grade III tumours (P = 0.015), but no correlation was found with tumour size, node status or level of epidermal growth factor receptor expression. A p53 mutation was associated with positive antibody staining in only two patients. Positive immunohistochemical staining using a p53 antibody may detect p53 protein expression, but this may not correlate directly with an underlying mutation in the hot spot region examined.     

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.     

Relationship of p53 gene alterations with tumor progression and recurrence in olfactory neuroblastoma

Olfactory neuroblastoma (ONB) is a rare neuroectodermal tumor whose clinical course is not effectively predicted by initial stage or grade; p53 tumor suppressor gene alterations have not been determined concerning the ONB pathobiology and recurrence. We analyzed 18 formalin-fixed, paraffin-embedded ONB specimens (12 primary tumors and six recurrences or metastases) from 14 patients for p53 alterations using immunohistochemistry for p53 and WAF1 together with topographic genotyping (selection of minute tissue targets from unstained sections, PCR [polymerase chain reaction] amplification of exons 5-8 followed by direct DNA sequencing). Sequential material representing tumor recurrence or metastasis was available in four cases to compare genetic alterations over time in the same patient. None of the cases showed strong, diffuse p53 immunostaining. Focal weak to moderate intensity staining was evident in nine of 14 cases. Mutations in p53 were not detected in any of the cases, suggesting hyperexpression of p53 wild-type protein. Hyperexpression was further confirmed by correlation of WAF-1 and p53 immunopositivity. Importantly, in four cases with recurrence or metastasis, tumors manifested p53 wild-type hyperexpression. It appears that p53 point mutation does not play an important role in the initial development of ONB; however, p53 wild-type hyperexpression may occur in subsets of ONB likely to show local aggressive behavior and a tendency for recurrence. Wild-type p53 hyperexpression may be an important event in later stages of ONB growth and progression.     

Comparison of p53 gene abnormalities in bilateral and unilateral breast cancer

BACKGROUND: The results of recent studies have suggested that p53 gene abnormalities are associated with carcinogenesis in several neoplasms. It is believed that bilateral breast carcinomas develop as a result of a different carcinogenetic mechanism and genetic environment from those of unilateral lesions. METHODS: p53 Gene abnormalities in bilateral primary breast cancer were detected by polymerase chain reaction-single strand comformation polymorphism (PCR-SSCP) analysis. A total of 76 paraffin embedded tissue specimens from 38 patients with bilateral primary breast cancer were examined, and 62 patients with unilateral breast cancer were analyzed as control subjects. The bilateral tumors were defined as primary, based on clinical parameters and the presence of an intraductal component. There were 13 patients with synchronous bilateral breast cancer and 25 with metachronous bilateral breast cancer. RESULTS: p53 Gene abnormalities were detected in 50% of the bilateral and 25.8% of the unilateral cases, and the difference was significant (P < 0.01, chi-square test). Abnormalities were detected in 56% of the metachronous cases, representing a much higher incidence than that of the unilateral cases (P < 0.001, chi-square test). The incidence of p53 gene abnormalities in the first and second tumors of the metachronous cases was 44% and 68%, respectively. The percentage of patients with a p53 gene abnormality and positive family history was higher for those with bilateral than with unilateral breast cancer (P < 0.01, chi-square test). CONCLUSION: These findings indicate that the genetic changes and mechanism of carcinogenesis in bilateral and unilateral breast cancer are different.     

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.     

Chromosome region 8p11-p21: refined mapping and molecular alterations in breast cancer

This review illustrates the use of experimental approaches combined with microscopy to study the biology of monogenean parasites. Studies of feeding, development, reproduction, and systematics have been based on gyrodactylids, flatworms infecting teleost fishes. In a contrasting system involving an amphibian host in a desert environment, analysis of adaptations to extreme conditions has focused on Pseudodiplorchis americanus. The unusual reproductive strategies, particularly the interactions between mother and offspring, are highlighted for both monogeneans. Species of Gyrodactylus are viviparous, maintaining up to three generations of embryos simultaneously in utero, and many of their reproductive specializations are related to progenesis. Embryo nutrition takes place via a metabolically-active syncytial uterine lining that has close association with the parental gut. Microscopy has also proved an essential adjunct to molecular studies of speciation and host specificity. P. americanus is ovoviviparous and the adaptations for embryo maintenance are unique. The primary keratin-type eggshell is replaced by a flexible secondary elastin capsule produced by the uterus; parental nutrients are transferred through cytoplasmic connections to the developing embryo. TEM has demonstrated unique adaptations of P. americanus to its micro-environments, including secretion of tegumental vesicles that provide protection from digestive enzymes during migration through the host gut. This paper highlights the potential of monogeneans for studies of fundamental biological principles.     

Chronic ultraviolet exposure-induced p53 gene alterations in Sencar mouse skin carcinogenesis model

Alterations of the tumor suppresser gene p53 have been found in ultraviolet radiation (UVR) related human skin cancers and in UVR-induced murine skin tumors. However, links between p53 gene alterations and the stages of carcinogenesis induced by UVR have not been clearly defined. We established a chronic UVR exposure-induced Sencar mouse skin carcinogenesis model to determine the frequency of p53 gene alterations in different stages of carcinogenesis, including UV-exposed skin, papillomas, squamous-cell carcinomas (SCCs), and malignant spindle-cell tumors (SCTs). A high incidence of SCCs and SCTs were found in this model. Positive p53 nuclear staining was found in 10/37 (27%) of SCCs and 12/24 (50%) of SCTs, but was not detected in normal skin or papillomas. DNA was isolated from 40 paraffin-embedded normal skin, UV-exposed skin, and tumor sections. The p53 gene (exons 5 and 6) was amplified from the sections by using nested polymerase chain reaction (PCR). Subsequent single-strand conformation polymorphism (SSCP) assay and sequencing analysis revealed one point mutation in exon 6 (coden 193, C-->A transition) from a UV-exposed skin sample, and seven point mutations in exon 5 (codens 146, 158, 150, 165, and 161, three C-->T, two C-->A, one C-->G, and one A-->T transition, respectively) from four SCTs, two SCCs and one UV-exposed skin sample. These experimental results demonstrate that alterations in the p53 gene are frequent events in chronic UV exposure-induced SCCs and later stage SCTs in Sencar mouse skin.     

Lymphoepithelial carcinoma of the larynx and hypopharynx: study of eight cases with relationship to Epstein-Barr virus and p53 gene alterations, and review of the literature

Eight cases of lymphoepithelial carcinoma (LEC) of the larynx and hypopharynx were evaluated for clinicopathologic features, and the presence of the Epstein-Barr virus (EBV) and p53 alterations. The seven men and one woman, all of non-Asian descent, averaged 64 years of age. Eighty-eight percent had histologically confirmed cervical lymph node metastasis at diagnosis. None had systemic disease. Seven of eight patients available for follow-up (mean, 17.7 months) were alive and free of disease, although one did develop recurrent tumor in the neck. Four tumors were composed, histologically, of pure LEC. Four others had foci of both LEC and conventional squamous cell carcinoma. All eight tumors exhibited alterations in p53 expression, but none was positive for EBV. Combining these 8 cases with the 15 previously published cases in the English literature indicate that LEC in this site is a rare, rather aggressive tumor, primarily of older adults (mean, 62 years) with a propensity for early cervical lymph node metastasis and eventual distant dissemination and death from disease in about one third of patients. Although p53 alterations are common and of no apparent prognostic significance, LEC at this site seems to have little, if any, relationship to the EBV in patients of non-Asian origin.     

p53 as a sensor of carcinogenic exposures: mechanisms of p53 protein induction and lessons from p53 gene mutations

The p53 tumor suppressor gene encodes a nuclear phosphoprotein with growth inhibiting properties, which is activated in cell exposed to various forms of DNA damaging stress. The development of human cancer often involves inactivation of this suppressor through various mechanisms, including gene deletions and point mutations. Most mutations impair the specific DNA-binding capacity of p53, therefore allowing cells to proliferate in conditions where cells with intact p53 function are suppressed or eliminated. Thus, mutation of p53 may provide a selective advantage for the clonal expansion of preneoplastic or neoplastic cells. The diversity of p53 mutations provides a valuable tool to identify important sources of cancer-causing mutation in the human setting. Mutagens and carcinogens damage the genome in characteristics ways, leaving "mutagen fingerprints" in DNA. Well-characterised examples of such "fingerprints" include G: C to T: A transversions in lung cancers in association with cigarette smoke, G: C to T: A transversions at codon 249 in liver cancers in association with dietary exposure to Aflatoxin B1 (AFB1) and CC: GG to TT: AA tandem dipyrimidine transitions in skin cancers in association with UVB exposure. In addition, mutations at different codons are not functionally equivalent. The availability of crystal structures of p53 protein represents an essential development in the understanding of the functional properties of p53 mutants. In the future, it is expected that analysis of p53 mutations may provide useful information for the diagnosis, prognosis and therapy of cancer.     

Association among p53 gene mutation, nuclear accumulation of the p53 protein and aggressive phenotypes in breast cancer

In order to reveal whether differences in the type and site of p53 gene mutations influence the function of the gene and tumor phenotype, we examined nuclear accumulation of the p53 protein immunohistochemically, loss of the other p53 allele by restriction-fragment-length polymorphism analysis, and histological grade of atypia in 52 breast-cancer tissue specimens in which the position and pattern of the mutation were identified. When mis-sense point mutations or deletions of 3n bases (n = 1, 2, ...), which did not cause a frameshift downstream, occurred within codons 110-180 or 234-285, containing highly conserved regions, the p53 protein was almost always (92%) accumulated in nuclei in a majority of the cancer cells. When these mutations occurred outside these regions, only 46% of the cases showed nuclear accumulation of the protein in a majority of cancer cells. In tumors with non-sense point mutations or deletion of 3n + 1 or 3n + 2 bases (n = 0, 1, 2, ...), which caused a downstream frameshift, nuclear accumulation of the p53 protein was absent in 93% of cases. Irrespective of the mutation site or pattern, a majority of cases showing p53 mutation revealed loss of heterozygosity on 17p13 (83%), which suggested they do not carry wild-type p53 allele, and the highest histological grade of atypia (90%). Regardless of differences in their protein-expression pattern, a majority of the p53 gene mutations were suggested to function in a recessive mode and to be involved in the development of histologically aggressive breast cancer.     

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.