Alteration of p53 gene in ovarian carcinoma: clinicopathological correlation and prognostic significance

Cancer-related Mutations with Local or Long-range Effects on an Allosteric Loop of p53

The tumor protein 53 (p53) is involved in transcription-dependent and independent processes. Several p53 variants related to cancer have been found to impact protein stability. Other variants, on the contrary, might have little impact on structural stability and have local or long-range effects on the p53 interactome. Our group previously identified a loop in the DNA binding domain (DBD) of p53 (residues 207-213) which can recruit different interactors. Experimental structures of p53 in complex with other proteins strengthen the importance of this interface for protein-protein interactions. We here characterized with structure-based approaches somatic and germline variants of p53 which could have a marginal effect in terms of stability and act locally or allosterically on the region 207-213 with consequences on the cytosolic functions of this protein. To this goal, we studied 1132 variants in the p53 DBD with structure-based approaches, accounting also for protein dynamics. We focused on variants predicted with marginal effects on structural stability. We then investigated each of these variants for their impact on DNA binding, dimerization of the p53 DBD, and intramolecular contacts with the 207-213 region. Furthermore, we identified variants that could modulate long-range the conformation of the region 207-213 using a coarse-grain model for allostery and all-atom molecular dynamics simulations. Our predictions have been further validated using enhanced sampling methods for 15 variants. The methodologies used in this study could be more broadly applied to other p53 variants or cases where conformational changes of loop regions are essential in the function of disease-related proteins.

Clinical relevance of TP53 hotspot mutations in high-grade serous ovarian cancers

BACKGROUND

Mutation of TP53 is the most frequent genetic alteration in high-grade serous ovarian cancer (HGSOC). The impact of hotspot mutations of TP53 and protein levels on patient outcomes in HGSOC has not been fully elucidated.

METHODS

The study population (n = 791) comprised of HGSOC samples with TP53 mutation from TCGA and other publicly available data. Univariate and multivariate cox proportional hazards regression analyses were used to select variables that were correlated with patient survival.

RESULTS

We assessed the effects of TP53 mutations based on type and individual hotspot mutations on patient outcomes in HGSOC. Only hotspot mutations were associated with outcomes. Three hotspot mutations: G266, Y163C, and R282, in aggregate were associated with a worsened overall and recurrence-free survival compared with other hotspot mutations (p < 0.0001 and p = 0.001), other non-hotspot missense mutations (p < 0.0001 and p = 0.008), truncated mutations (p < 0.0001 and p = 0.001), and all other mutations (p < 0.0001 and p = 0.001). Specific hotspot mutations were associated with different protein expression patterns consistent with different functions.

CONCLUSIONS

This study provides evidence that individual TP53 hotspot mutations have different impact on HGSOC patient outcomes and potentially TP53 function. Thus the status of particular TP53 aberrations could influence response to therapy and selection of therapeutic agents.

P53 Expression, Dna Ploidy and Mitotic Index as Prognostic Factors in Patients with Epithelial Ovarian Carcinoma

Aims and Background

Biological variables linked to genomic instability were examined and related to survival in 52 patients affected by ovarian carcinoma and nine patients with low malignant potential tumors (LMP).

Methods

DNA ploidy was measured by image cytometry in isolated neoplastic cells; the mitotic index was measured in Feulgen-toluidine blue-stained sections and p53 was investigated by immunohistochemistry.

Results

Twenty-five tumors (4 LMP) were peridiploid (ploidy <2.25c), 22 tumors (4 LMP) were hyperdiploid (2.25c>ploidy<2.9c) and 14 (1 LMP) had high ploidy (≥2.9c). Ml ranged from 0.3 to 24.2 with a mean of 1.8 for LMP and 6.8 for carcinomas (P <0.001). Widespread p53 overexpression was detected in 49% of carcinomas and in none of the LMP tumors.

Conclusions

Survival analysis performed in patients with carcinomas indicated that, of the examined biological variables, only Ml was moderately associated with survival in a subgroup of early-stage patients.

TP53 mutations in epithelial ovarian cancer

Genomic sequencing analyses of a variety of human cancers have revealed that massive mutations of cancer-relevant genes are the major alterations in cancerous cells, and their mutation frequencies or rates are highly associated with the development, progression, metastasis, and drug resistance of cancers as well as their clinical outcomes and prognosis. One predominant genetic alternation in human epithelial ovarian cancer (EOC) is the mutation of TP53 that encodes the tumor suppressor p53 protein. This essay will review the most recent progress in understanding the role of TP53 mutations in development, progression, and metastasis of EOC, and discuss the potential of TP53 mutations as diagnostic and prognostic biomarkers as well as therapeutic targets for EOC.

The consequence of oncomorphic TP53 mutations in ovarian cancer

Ovarian cancer is the most lethal gynecological malignancy, with an alarmingly poor prognosis attributed to late detection and chemoresistance. Initially, most tumors respond to chemotherapy but eventually relapse due to the development of drug resistance. Currently, there are no biological markers that can be used to predict patient response to chemotherapy. However, it is clear that mutations in the tumor suppressor gene TP53, which occur in 96% of serous ovarian tumors, alter the core molecular pathways involved in drug response. One subtype of TP53 mutations, widely termed gain-of-function (GOF) mutations, surprisingly converts this protein from a tumor suppressor to an oncogene. We term the resulting change an oncomorphism. In this review, we discuss particular TP53 mutations, including known oncomorphic properties of the resulting mutant p53 proteins. For example, several different oncomorphic mutations have been reported, but each mutation acts in a distinct manner and has a different effect on tumor progression and chemoresistance. An understanding of the pathological pathways altered by each mutation is necessary in order to design appropriate drug interventions for patients suffering from this deadly disease.

Prognostic biomarkers in ovarian cancer

Epithelial ovarian cancer (EOC) remains the most lethal gynecological malignancy despite several decades of progress in diagnosis and treatment. Taking advantage of the robust development of discovery and utility of prognostic biomarkers, clinicians and researchers are developing personalized and targeted treatment strategies. This review encompasses recently discovered biomarkers of ovarian cancer, the utility of published prognostic biomarkers for EOC (especially biomarkers related to angiogenesis and key signaling pathways), and their integration into clinical practice.

Prognostic significance of human epididymis protein 4 in epithelial ovarian cancer

OBJECTIVE

The purpose of this study was to evaluate the prognostic significance of serum human epididymis protein 4 (HE4) level in patients with epithelial ovarian cancer.

STUDY DESIGN

A total of 78 women diagnosed with a pelvic mass and operated on in our institute comprised our cohort. Forty-five of these were diagnosed with epithelial ovarian cancer and treated with debulking surgery, followed by taxane and platinum-based chemotherapy as clinically indicated. Preoperatively obtained serum samples were analyzed for levels of HE4 and CA125.

RESULTS

The elevated serum HE4 level was related to advanced stage and serous type of cancer. The median duration of the follow-up was 35.1 months. In advanced stage, the median progression-free survival (PFS) of patients with elevated serum HE4 levels was 20.1 months (95% CI, 15.7-24.6 months), whereas that of patients with normal serum HE4 level was 24.2 months (95% CI, 13.9-34.6 months) (p=0.029). Independent predictors for PFS in patients with advanced stage EOC included serum HE4 level (hazard ratio 2.24; 95% CI, 1.14 to 6.84; p=0.048).

CONCLUSIONS

Our results demonstrated that an elevated serum HE4 level was related to the advanced stage of epithelial ovarian cancer. An elevated serum level of HE4 is a poor prognostic factor for PFS in patients with epithelial ovarian cancer who were treated with debulking surgery and adjuvant taxane and platinum-based chemotherapy. The serum HE4 level is a promising indicator for the progression of cancer as well as a biomarker for the detection of epithelial ovarian cancer.

P53, bcl-2, ki-67 li (labeling index) status in benign, proliferative, and malignant ovarian surface epithelial neoplasms

OBJECTIVE

Approximately 50% of human malignancies present with mutations in p53, which is the most common tumor suppressor gene involved with human malignancies. Bcl-2 is a protooncogene, and expression of its protein product is associated with a better prognosis in several malignancies. Ki-67 is a marker of cellular proliferation. The purpose of this study was to determine whether simultaneous detection of p53, bcl-2 and Ki-67 using immunohistochemical staining can be used as a diagnostic factor in the assessment of human ovarian epithelial tumors.

MATERIALS AND METHODS

The study was performed on formalin-fixed, paraffin-embedded tissue samples from 75 epithelial ovarian tumors, 15 serous cystadenomas, 15 mucinous cystadenomas, 5 borderline serous cystadenomas, 5 borderline mucinous cystadenomas, 15 serous cystadenocarcinomas, 15 mucinous cystadenocarcinomas and 5 endometrioid carcinomas. Immunohistochemical staining was performed using monoclonal antibodies against p53, bcl-2, and Ki-67(MIB1).

RESULTS

Anti-p53 reactivity was observed in 14 tumors, all of which were malignant tumors, and no reactivity was observed in borderline or benign tumors. Overexpression of bcl-2 was observed in 12 benign neoplasms (40%), 5 of which were borderline (50%), but was not observed in any of the malignant tumors. There was a statistically significantly higher level of Ki-67 LI positivity in the malignant tumors than in the benign and borderline tumors (p<0.005).

CONCLUSION

These data show significant differences in the expression of these markers in ovarian tumors and suggest a possible role for these tumor-associated genes as supplemental tools in diagnostic pathology. Furthermore, our findings support the redesignation of low malignant potential tumors (current nomenclature) to benign ovarian carcinoma.

Prognostic value and clinicopathological significance of p53 and PTEN in epithelial ovarian cancers

OBJECTIVE

The aim of the study was to evaluate the prognostic significance of p53 and PTEN in patients with epithelial ovarian cancer who were treated with taxane and platinum-based chemotherapy.

METHODS

Retrospectively collected paraffin blocks from 151 epithelial ovarian cancer patients treated with debulking surgery followed by taxane and platinum chemotherapy were analyzed. Expression of p53 and PTEN was assessed by immunohistochemistry. The staining pattern was correlated with clinicopathological variables.

RESULTS

Overexpression of p53 was found in 80 of the 151 cases (53.0%), and it was related to stage, histology and grade. Reduced expression of PTEN was found in 104 of the 151 cases (68.9%), and it was not related to any clinicopathological factors other than age. In survival analysis, stage (p=0.001), residual tumor (p=0.045), lymph node metastases (p=0.012), and PTEN expression (p=0.009) were significant predictors for disease-free survival (DFS). The median DFS of patients with reduced PTEN expression was 20 months (range, 3-71 months), whereas that of patients with normal PTEN expression was 53 months (range, 2-81 months).

CONCLUSIONS

Reduced PTEN expression is a poor prognostic factor for DFS in patients with epithelial ovarian cancer who were treated with debulking surgery and postoperative taxane and platinum chemotherapy.

Both germ line and somatic genetics of the p53 pathway affect ovarian cancer incidence and survival

PURPOSE

Although p53 is one of the most studied genes/proteins in ovarian carcinomas, the predictive value of p53 alterations is still ambiguous.

EXPERIMENTAL DESIGN

We performed analyses of the TP53 mutational status and its protein expression using immunohistochemistry. Moreover, the single nucleotide polymorphism SNP309 in the P2 promoter of the MDM2 gene was investigated. We correlated the results with age of onset and outcome from 107 patients with ovarian carcinoma.

RESULTS

In our study, we identified a large group of patients with p53 overexpression despite having a wild-type gene (49% of all patients with wild-type TP53). This was associated with a significantly shortened overall survival time (P = 0.019). Patients with p53 alterations (especially those with overexpression of wild-type TP53) were also more refractory to chemotherapy compared with patients with normal p53 (P = 0.027). The G-allele of SNP309 is associated with an earlier age of onset in patients with estrogen receptor-overexpressing FIGO stage III disease (P = 0.048). In contrast, in patients with FIGO stage III disease, a weakened p53 pathway (either the G-allele of SNP309 or a TP53 mutation) was correlated with increased overall survival compared with patients whose tumors were wild-type for both TP53 and SNP309 (P = 0.0035).

CONCLUSION

Our study provides evidence that both germ line and somatic alterations of the p53 pathway influence the incidence and survival of ovarian carcinoma, and it underscores the importance of assessing the functionality of p53 in order to predict the sensitivity of platinum-based chemotherapies and patient outcome.

Human papilloma virus (HPV) status, p16INK4a, and p53 overexpression in epithelial malignant and borderline ovarian neoplasms

This investigation is the first to evaluate simultaneously human papilloma virus (HPV) status, p16(INK4a), and p53 immunoreactivity in epithelial ovarian neoplasms. The results were analyzed and correlated with histological type, histological grade, and survival of patients. Subtypes considered are papillary serous and mucinous. Polymerase chain reaction (PCR) analysis, performed in our previous study, had already demonstrated a small number of HPV-positive epithelial ovarian neoplasms. No significant correlation was found between the presence of HPV DNA and subtypes of ovarian neoplasms; thus, HPV cannot be considered responsible for epithelial ovarian neoplasm. Since p16 immunoreactivity was present in many other HPV-negative cases of epithelial ovarian neoplasms, this study suggests that p16 overexpression in some neoplasms of the female genital tract is not related to HPV carcinogenesis. A higher p53 expression rate observed between borderline and malignant serous tumors and between serous and mucinous neoplasms can confirm a recent dualistic model of ovarian carcinogenesis. According to this theory, low-grade serous carcinomas (serous intraepithelial carcinomas, serous borderline neoplasm, and ovarian mucinous neoplasms) (type I tumors) develop from mutations of KAS and BRAF, while high-grade serous carcinomas (type II tumors) develop from mutation of p53. In malignant neoplasms, for univariate analysis, patient survival seems to be related to p53, strong and diffuse p16 overexpression, and the stage of development of neoplasms at the diagnosis. In multinomial logistic regression, used to evaluate the role of staging, grading, p16 and p53 immunopositivity as predictor variables of unfavorable outcome of the disease, only p16 positivity was significantly related to the poor prognosis of the cancer.

[Overexpression and prognostic value of p53 and HER2/neu proteins in benign ovarian tissue and in ovarian cancer]

BACKGROUND AND OBJECTIVE

To investigate the prognostic value of p53 and HER2/neu overexpression in epithelial ovarian cancer (EOC).

PATIENTS AND METHOD

p53 and HER2/neu immunostaining were performed in 198 tissue samples, 124 EOC, 44 benign ovarian tumors and 30 normal ovaries. Nuclear p53 and membranous HER2/neu immunostaining were evaluated.

RESULTS

Neither p53 nor HER2/neu overexpression was seen in the benign ovarian tumors. HER2/neu immunostaining was observed in one normal ovary. P53 overexpression was found in 25% EOC and was related with advanced stage, endometrioid, clear cell and undifferentiated types, grade G3, and sub-optimal surgery. HER2/neu immunostaining was observed in 24.2% and it was associated with advanced stage, clear cell and undifferentiated types, and suboptimal surgery. Both, p53 and HER2/neu overexpression decreased overall and progression-free survival, but in the multivariant analysis, only HER2/neu overexpression was an independent prognostic factor of overall survival (RR = 2.8; 95% confidence interval [CI], 1.2-5.6) and recurrence (RR = 2.8; 95% CI, 1.1-7.1). Simultaneous p53 and HER2/neu overexpression made the prognosis worse (p < 0.01).

CONCLUSIONS

HER2/neu overexpression (but not p53 overexpression) is a major prognostic factor in EOC.

Analysis of p53 protein expression levels on ovarian cancer tissue microarray using automated quantitative analysis elucidates prognostic patient subsets

BACKGROUND

p53 protein is regarded as a valuable prognostic marker in cancer with a potential use as a molecular target. Here, we sought to determine the prognostic value of p53 in ovarian cancer using a novel method of compartmentalized in situ protein analysis.

PATIENTS AND METHODS

A tissue array composed of 141 advanced stage ovarian cancers uniformly treated was constructed. For evaluation of p53 protein expression, we used an immunofluorescence-based method of automated in situ quantitative measurement of protein analysis (AQUA).

RESULTS

High nuclear p53 expression levels were associated with better outcome for overall survival (OS) (P = 0.0023) and disease-free survival (P = 0.0338) at 5-years. High cytoplasmic p53 expression levels were associated with better outcome for OS (P = 0.0002). In multivariable analysis, high nuclear and high cytoplasmic p53 level with International Federation of Gynecology and Obstetrics (FIGO) stage were the most significant predictor variables for OS and high nuclear p53 level with FIGO stage were the significant predictor variables for disease-free survival.

CONCLUSIONS

Assessment of the prognostic value of p53 protein levels using conventional immunohistochemistry is limited by the nonquantitative nature of the method. AQUA provides precise estimation of p53 protein levels and was able to elucidate the association of p53 protein levels and ovarian cancer prognosis.

Geographical Variations in TP53 Mutational Spectrum in Ovarian Carcinomas

The TP53 gene mutational spectrum in human tumours shows variations related to tissue of origin, carcinogen exposure or molecular background. We have compared TP53 mutations in ovarian carcinomas from different geographical regions; this study was based on data extracted and verified from the IARC database (R10, 2005), and on our results from 127 carcinomas. In total 873 mutations were evaluated. Tumours from Japan and Korea had a higher frequency of exon 7 mutations (38%vs 25%, p = 0.011) and lower frequency of exon 8 mutations (11%vs 29%, p = 0.0003) than those from Western countries; they were particularly different from Norwegian tumours which showed the lowest proportion of exon 7 (19%, p = 0.001) and highest proportion of exon 8 (37%, p < 0.0001) mutations. There were also differences in the profile of TP53 hotspots. The third hotspot in tumours from Poland was amino acid (AA) 176 (8.2% of substitutions vs 1.7% in other countries, p < 0.001), while in tumours from the UK it was AA 220 (8.9%vs 2.3%, p < 0.001). Codon 273 was the only apparent hotspot in the Norwegian tumours, while it was rarely mutated in Polish and Asian tumours. In contrast to other data tumours from Norway presented with 273(HIS) codon (82% of mutations at AA 273, p = 0.002), while tumours from the UK shared the 273(CYS) codon (80%, p < 0.001). Further analysis of TP53 gene mutations in ovarian cancer by geography could provide greater insights.

Molecular predictors of response and outcome in ovarian cancer

A major problem in clinical management of patients with epithelial ovarian cancer (EOC) is the largely unpredictable response to first-line treatment and the occurrence of relapse after complete initial response, associated with broad cross-resistance to even structurally dissimilar drugs. During tumor development and progression, multiple genic alterations take place that might contribute specifically to the treatment response and eventually impact on disease outcome. One area of intense research is the identification of molecular markers to accurately assess the prognosis of EOC patients and to define innovative therapeutic strategies. A large survey of recent published data indicates the need to revisit traditional molecular markers with respect to their contribution to the assessment of overall survival in selected populations. Furthermore, recent technological developments that enable simultaneous measurement of many parameters ("omic" approaches) hold the promise of identifying new molecular prognostic and predictive markers.

Clinicopathologic analysis of early-stage sporadic ovarian carcinoma

The reported experience with early-stage (FIGO stage I/II) ovarian carcinoma (OC) is limited given that the majority of women with OC are diagnosed at an advanced stage. There has not been an extensive review of these tumors, and since the pathologic criteria differentiating invasive and borderline tumors have evolved over time, the issue of whether a proportion of these tumors should be reclassified has not been addressed. We identified patients with stage I/II invasive OC who underwent primary surgical management at Memorial Sloan-Kettering Cancer Center from 1980 to 2000. Patients known to have a BRCA mutation or a family history of breast/ovarian cancer were excluded. Hematoxylin and eosin slide review, blinded to clinical outcomes, using current diagnostic criteria for ovarian carcinomas and borderline ovarian tumors, was performed. Progression-free survival (PFS) and disease-specific survival (DSS) were estimated and compared. Hematoxylin and eosin slides were reviewed for 140 of the 145 patients identified. The diagnosis was changed to borderline (low malignant potential) in 41 cases (29.3%). Twenty-nine (70.7%) of 41 changes in diagnosis involved endometrioid and mucinous tumors. This was attributable to the application of recently revised criteria for distinguishing borderline tumors from carcinomas. None of the originally diagnosed clear cell carcinomas was reclassified as borderline. The distribution of histologic subtypes among the 94 carcinomas included 26 serous (27.7%), 25 clear cell (26.6%), 22 endometrioid (23.4%), 10 mixed (10.6%), 6 mucinous (6.4%), 2 malignant Brenner (2.1%), and 3 adenocarcinomas, not otherwise specified (3.2%). Adjuvant therapy was given to 84 (89.4%) of the 94 patients with carcinomas. The 5-year PFS and DSS were significantly greater for the group of cases that was reclassified as borderline (4.5% vs. 26.2% progressed [P = 0.006]; 4.5% vs. 25.6% died [P = 0.003]). The 5-year PFS and DSS were significantly worse for carcinomas with a TP53 mutation (22.6% vs. 41.2% progressed [P = 0.04]; 21.7% vs. 24.7% died [P = 0.04]). There were no statistically significant differences in outcome between stages I versus II, tumor grades, clear cell histology versus other, and stage IC preoperative versus intraoperative rupture. We concluded that a large number of cases originally diagnosed as early-stage sporadic OC were borderline tumors. Clear cell histology does not confer a worse prognosis compared with other histologies. The presence of a TP53 mutation was an adverse prognostic indicator.

TP53 mutations in early-stage ovarian carcinoma, relation to long-term survival

We conducted the present study to evaluate the frequency and prognostic importance on long-term survival of TP53 mutations and TP53 protein accumulation in a cohort of 178 patients with early-stage ovarian carcinomas. TP53 mutations scored as aberrant temporal temperature gradient gel electrophoresis pattern from all exons were observed in 39.9% of the tumours. Full screening of exons 5–8, followed by sequencing, was successful in 135 cases, and 48 mutations altering the protein were detected in 39 cases (28.9%). TP53 mutations were slightly less common in the Federation of Gynecologists and Obstetricians stage IA than in IB/IC (P=0.05). No significant correlations with histological type, grade of differentiation, DNA ploidy status or age at diagnosis were found. TP53 protein accumulation analysed by immunohistochemistry was found in 32.6% of all tumours, and was a poor predictor of TP53 mutations with 56.4% sensitivity, 77.1% specificity, 50% positive predictive value and 81.3% negative predictive value. Neither TP53 mutations nor TP53 protein accumulation influenced the prognosis significantly in this group of patients.

A review of p53 expression and mutation in human benign, low malignant potential, and invasive epithelial ovarian tumors

BACKGROUND

In the current study, the authors present pooled data from studies that investigated p53 protein expression and/or mutation in human epithelial ovarian tumors.

METHODS

The English literature in the MEDLINE, PubMed, and Ingenta databases was searched to the end of the year 2000 to identify relevant studies. Data were pooled across eligible studies, and the prevalence of p53 expression and mutation among benign, low malignant potential (LMP), and invasive tumors was determined. Prevalence estimates by tumor histology, International Federation of Gynecology and Obstetrics (FIGO) stage, and grade also were calculated.

RESULTS

The pooled prevalence estimate for p53 overexpression among epithelial ovarian carcinomas was 51% (95% confidence intervals [95% CI], 50-53%) compared with 17% (95% CI, 15-20%) among LMP tumors and 7% (95% CI, 5-10%) among benign tumors. p53 mutation prevalence estimates were 45% (95% CI, 42-47%), 5% (95% CI, 2-9%), and 1% (95% CI, 0-5%), respectively, for invasive, LMP, and benign tumors. The prevalence of these p53 abnormalities was found to be associated positively with increasing tumor grade and stage. Differences based on histologic subtype also were found.

CONCLUSIONS

Although these pooled estimates might appear to offer support for various hypotheses regarding the role of p53 in ovarian carcinoma, the limitations inherent in these data hamper the interpretation of the significance of any of the findings. Future studies will require innovative methods to address the limitations of many previous investigations and more comprehensive investigation into defective tumor suppression mechanisms.

Correlation of p53 immunostaining in primary and residual ovarian cancer at the time of positive second-look laparotomy and its prognostic role: a Southwest Oncology Group ancillary study

OBJECTIVE

The objective of this study was to verify the correlation between p53 immunostaining at initial diagnosis and at positive reassessment after completing platinum-based chemotherapy and to assess prognostic differences between patients whose tumors display positive immunostaining versus those that have negative immunostaining at such reassessment.

METHODS

This study made use of samples from patients entered into a prospective randomized study of the Southwest Oncology Group (SWOG 8835) that treated patients with minimal residual disease at second-look laparotomy with either intraperitoneal (ip) mitoxantrone or fluorodeoxyuridine (FUDR). Unstained slides from tumor obtained at the initial diagnosis and at reassessment were retrospectively requested from individual institutions. The degree of nuclear staining was determined using the anti-p53 mouse monoclonal antibody Pab1801 and previously published techniques, with a cutoff of 10% or more staining of tumor cell nuclei for a positive result. Cox model regression analysis was performed for overall survival and progression-free survival, with p53 status, ip treatment, and baseline CA125 as independent variables.

RESULTS

p53 determination was feasible in 22 patients both at diagnosis and at the second-look samples; 9 additional patients had only either sample available. Since concordance between the 10 negative and 12 positive immunostained samples was 100%, all 31 patients were considered in the Cox model. The death hazard ratio of p53-positive versus p53-negative patients was 4.18 (two-sided P value of 0.006).

CONCLUSION

p53 immunostaining at second-look laparotomy correlates with the immunostaining at diagnosis. In this series confined to patients with minimal residual disease after initial therapy subjected to second-line intraperitoneal treatment, it appears to identify a poor prognostic (positive) subset for survival.

The prognostic importance of p53, bcl-2, and bax in early stage epithelial ovarian carcinoma treated with adjuvant chemotherapy

Epithelial ovarian cancer is one of the major causes of death among women. The increasing knowledge about molecular events involved in the early stages of ovarian tumorigenesis may provide the basis for management in the future. In a series of 109 patients with epithelial carcinomas in FIGO stages IA-IIC, a number of clinicopathologic prognostic factors (age, FIGO stage, histopathologic type, and tumor grade) were studied in relation to the biologic factors p53, bcl-2, and bax, which are important regulators of apoptosis. Immunohistochemical techniques were used. All the patients received adjuvant chemotherapy after the primary surgery. Univariate analysis showed that expression of p53 was significantly associated with tumor grade (P = 0.014), probability of persistent disease (P = 0.016), and cancer-specific survival rate (P = 0.007). Positive bcl-2 staining was associated with endometrioid tumor subtype (P = 0.029) and a favorable tumor grade distribution (P = 0.034), but not with the survival status. The combined p53-bcl-2 expression was related to histopathologic subtype (P = 0.032), tumor grade (P = 0.011), persistent disease (P = 0.014), and risk of dying due to the disease (P = 0.039). The bax status was not a prognostic factor, but the combined p53-bax expression showed an association with FIGO stage (P = 0.014), tumor grade (P = 0.034), persistent disease (P = 0.006), and risk of dying due to the disease (P = 0.039). The combined bcl-2-bax expression was related to histopathologic subtype (P = 0.045) and tumor grade (P = 0.022). In a multivariate Cox analysis, tumor grade (P = 0.014), and p53 status (P = 0.020) were independent and significant prognostic factors with regard to the cancer-specific survival rate.

Heterogeneity of ovarian cancer: relationships among histological group, stage of disease, tumor markers, patient characteristics, and survival

Epidemiological studies have established associations between various reproductive factors and risk of ovarian cancer; it has also been observed that some of these risk factors are only associated with specific histological subgroups. To investigate the correlation of genetic alterations with these risk factors, we examined a consecutive series of 158 ovarian cancer cases treated at the University of Kentucky (1990-96). Common molecular genetic alterations (LOH on chromosome 17, P53 alterations, K-RAS mutations), histological and clinical characteristics of the disease, demographic patient information and survival were evaluated. These latter data were from the Kentucky Cancer Registry. Univariate analysis showed higher frequencies of chromosome 17 loss and P53 mutations in tumors of advanced stage and grade, and in older and post-menopausal women. Non-mucinous tumors were more likely to be classified as late stage, high-grade cancers, and to have chromosome 17 loss and P53 mutations. Survival analysis indicated that stage was the only independent significant variable. When stage was the outcome variable in multiple logistic regression analysis, histology and chromosome 17 loss were significantly associated with poor survival. This case-case study provides evidence that ovarian cancers of mucinous and non-mucinous histology are significantly different with respect to clinical characteristics, survival and molecular alterations. It also lends support to the hypothesis that ovarian cancer is a heterogeneous disease with distinct etiological factors and clinical outcomes, which may require different approaches to treatment.

Reduced expression of BAX is associated with poor prognosis in patients with epithelial ovarian cancer: a multifactorial analysis of TP53, p21, BAX and BCL-2

Traditional clinicopathological features do not predict which patients will develop chemotherapy resistance. The TP53 gene is frequently altered in ovarian cancer but its prognostic implications are controversial. Little is known on the impact of TP53-downstream genes on prognosis. Using molecular and immunohistochemical analyses we examined TP53 and its downstream genes p21, BAX and BCL-2 in ovarian tumour tissues and have evaluated the results in relation to clinico-pathological parameters, clinical outcome and response to platinum-based chemotherapy. Associations of tested factors and patient and tumour characteristics were studied by Spearman rank correlation and Pearsons chi2 test. The Cox proportional hazard model was used for univariate and multivariate analysis. The associations of tested factors with response was tested using logistic regression analysis. TP53 mutation, p21 and BCL-2 expression were not associated with increased rates of progression and death. Expression of TP53 was associated with a shorter overall survival only (relative hazard rate [RHR] 2.01, P = 0.03). Interestingly, when combining TP53 mutation and expression data, this resulted in an increased association with overall survival (P = 0.008). BAX expression was found to be associated with both progression-free (RHR 0.44, P = 0.05) and overall survival (RHR 0.42, P = 0.03). Those patients who simultaneously expressed BAX and BCL-2 had a longer progression-free and overall survival compared to patients whose tumours did not express BCL-2 (P = 0.05 and 0.015 respectively). No relations were observed between tested factors and response to platinum-based chemotherapy. We conclude that BAX expression may represent a prognostic indicator for patients with ovarian cancer and that the combined evaluation of BAX and BCL-2 may provide additional prognostic significance.

P53 mutation does not affect prognosis in ovarian epithelial malignancies

Mutations of the p53 tumour suppressor gene have been found in most human cancers, including ovarian epithelial malignancies. This study investigated whether the presence or absence of p53 mutation was associated with outcome following platinum-based chemotherapy in patients with ovarian cancer. DNA samples from tumour tissue and blood were obtained from 73 patients with primary tumours, 50 of whom received platinum-based adjuvant chemotherapy. Single-strand conformation polymorphism analysis and direct DNA sequencing of exons 5-8 detected mutations in 44% (32 of 73) of tumours. These were more common in late-stage (III or IV) than in early-stage disease (I or II) (p=0.03). There was no association with histological type, volume of residual disease following surgery, or initial CA125 levels. No significant association was found between p53 status and overall survival or disease-free survival following chemotherapy. Likewise, there was no correlation between p53 mutation and response to chemotherapy as defined by normalization of CA125 levels. Tumours with p53 missense mutations recurred within a significantly shorter time than those with normal p53 (p=0.04). In addition, there was a tendency for tumours with missense mutations to have a shorter disease-free survival than those with non-missense mutations, although this did not reach statistical significance (p=0.07).

p53 mutation is infrequent in clear cell carcinoma of the ovary

OBJECTIVE

p53 gene alteration has been extensively studied in epithelial ovarian cancer. However, its occurrence in clear cell carcinoma, an infrequent histologic subtype of epithelial ovarian cancer, is rarely reported. The aim of this study is to determine the status of p53 gene alteration in this distinct type of ovarian carcinoma.

METHODS

Paraffin blocks of tumors from 38 patients with primary or recurrent ovarian clear cell carcinoma were studied for p53 alteration. All these tumors were subjected to immunohistochemical and molecular analysis. Two monoclonal antibodies (DO-7 and PAb 1801) were used for immunohistochemical staining. Genomic DNAs extracted from paraffin blocks of the 38 tumors were subscribed for a nested polymerase chain reaction/single-strand conformation polymorphism (PCR/SSCP) analysis. Tumors showing band shift on SSCP were further prepared for DNA sequencing to determine the site of mutation.

RESULTS

Overexpression of p53 was observed in only one stage III clear cell carcinoma. However, focal positive p53 staining was noted in another five tumors. Of the six tumors showing positive immunohistochemistry, p53 alterations were noted in four tumors. Three tumors revealed a missense point mutation: two were in exon 7 (TCT(227) --> TTT and GGC(245) --> AGC) and one was in exon 5 (CGC(156) --> CAC). Another tumor revealed a 12-bp deletion in two possible ways: it might involve the last four codons at the 3' end of exon 4 (nucleotides 12,288-12,299) or it might cross over the splice junction between exon 4 and intron 4 (nucleotides 12,290-12,301). The former would result in a predicted protein product of 389 amino acids whereas the latter would cause a frameshift in the gene sequence and would result in a truncated protein.

CONCLUSION

Mutations in p53 appear to be much less frequent in clear cell carcinoma than in other histologic types of epithelial ovarian cancer. We suggest that p53 alterations may not play an important role in the development of clear cell carcinoma.

Atypical epithelial changes and mutant p53 gene expression in ovarian endometriosis

It has been reported that cases of ovarian endometriosis those with epithelial cytological atypia have potential for malignant transformation. This study was planned to determine the incidence of atypical endometriosis and its cytological criteria, to evaluate the malignant potential of atypical endometriosis via immunohistochemical methods (p53). In this study we evaluated 140 samples obtained from 120 cases of ovarian endometriosis and 10 ovarian endometrioid carcinomas that have been previously diagnosed histopathologically. We re-evaluated endometriosis cases with respect to their epithelial and stromal features, existence of acute or chronic inflammatory cells in endometriotic epithelium or stroma and other accompanying histological findings. We observed atypia in 7 (5.8%) cases; reactive atypia in 37 (30.8%) cases, no atypia in 76 (63.4%) cases. We evaluated immunohistochemical p53 expression in 7 atypical cases, 37 reactive atypical cases, and in 10 of those without atypia and in 10 endometrioid carcinoma cases. We noted no staining in cases with atypia, reactive atypia and without atypia while 3 cases of endometrioid carcinoma had positive staining for p53. We concluded that prominent nucleolus and angulation of nuclear contour could be added to criteria of atypia that were mentioned before in the literature. In our study, even though p53 expression could not be shown with immunohistochemical methods in atypical endometriotic cases; it can not be determined that atypical endometriosis lesions are not premalignant. Still, endometriosis cases should be evaluated carefully by the pathologist for foci of cytological atypia and it should be kept in mind that malignant transformation might occur in these atypical endometriosis cases.

p53 and related proteins in epithelial ovarian cancer

We conducted a retrospective immunohistochemical evaluation of the prognostic significance of the expression of p53 and the related proteins Bax, Bcl-2, growth arrest and DNA damage (Gadd45), murine double minute 2 (Mdm2) and p21(WAF1/CIP1) in chemonaive tumours taken from 66 patients with ovarian cancer. Ki-67 expression (a marker of cell proliferation) was also evaluated immunohistochemically, while apoptosis within malignant cells was determined with the terminal deoxynucleotidyltransferase-mediated dUTP nick-end labelling (TUNEL) assay. The expression of each of the following proteins was significantly associated in the tumours (P < 0.05 unless otherwise stated): Bax with Bcl-2 (P < 0.01); Bax with Mdm2; p21(WAF1/CIP1) with Gadd45 (P < 0.01); p21(WAF1/CIP1) with p53; p53 with Mdm2. Univariate analysis showed that expression of p53, Bax, bulk residual disease and International Federation of Gynecology and Obstetricians (FIGO) stage were all strongly correlated with response to chemotherapy (P < 0.01). Similarly, the FIGO stage and Ki-67 expression (P < 0.01), as well as pathological subtype and bulk residual disease (P < 0.05), were prognostic factors for disease progression. The FIGO stage and Ki-67 expression were significant prognostic factors for overall survival (P < 0.01), with Gadd45 expression and pathological subtype also significant (P < 0.05) in a univariate analysis. Multivariate analysis for response to chemotherapy showed that expression of p53, Bax and FIGO stage were all independent prognostic factors (P < 0.01). The FIGO stage was the most important independent prognostic factor for progression and survival on multivariate analysis (P < 0.01). However, Ki-67 expression was also an independent prognostic factor for disease progression (P < 0.05) and approached significance for survival (P = 0.055). Taken together, these data suggest that determination of Ki-67 expression could supplement established prognostic factors.

DNA replication errors are frequent in mucinous cystadenocarcinoma of the ovary

To elucidate the genetic etiology of sporadic epithelial ovarian carcinoma, we examined replication errors (RER) in its two common types, serous cystadenocarcinoma (SAC) and mucinous cystadenocarcinoma (MAC). The subjects were 63 patients with sporadic epithelial ovarian carcinoma, consisting of 34 patients with SAC and 29 with MAC. The specimens were formalin-fixed and paraffin-embedded tissues from the ovary. The presence of RER was examined by polymerase chain reaction using 5 microsatellite markers. Of the 61 informative patients with ovarian carcinoma, RERs were observed at greater than or equal to 1 locus in 15 patients (25%). Four of the 32 SAC patients (13%) were RER-positive, and 11 of the 29 MAC patients (38%) were RER-positive, the incidence being significantly higher in the latter than in the former (P < 0.05). The incidence of RER was not related to the patients' age, stage, histologic grade, or prognosis. The MAC patients in stages I and II showed a relatively high incidence of RER (30%). These results suggest that RER are involved in the development and/or progression of MAC among sporadic epithelial ovarian carcinoma in its relatively early stage.

Prognostic significance of p53 and p21(waf1/cip1) immunoreactivity in epithelial cancers of the ovary

OBJECTIVES

Theprognostic value of p53 expression in epithelial ovarian cancer remains unresolved. We hypothesized that prognosis may relate more to expression of p21(waf1/cip1), the major downstream effector of p53, which can also be induced through p53-independent mechanisms. We therefore studied the relationship of p53 and p21(waf1/cip1) expression in epithelial ovarian cancers to clinicopathological variables and prognosis.

METHODS

Fixed, embedded tumors from 85 patients with untreated, primary epithelial ovarian cancer were immunostained with antibodies to p53 and p21(waf1/cip1). Expression was correlated with clinicopathological features and prognosis. Survival curves were calculated by the Kaplan-Meier method and compared using the log-rank test for p53, p21(waf1/cip1), and all combinations of expression of the two markers.

RESULTS

Sixty-two percent of tumors expressed p53, and 42% expressed p21(waf1/cip1). There was no correlation between p53 and p21(waf1/cip1) expression. Advanced stage, grade, age >/=50, and p53 expression were associated with worse disease-free survival. Patients whose tumors were p53(+)/waf1(-), however, had a particularly strong association with poorer disease-free survival when compared with other combinations of p53 and p21(waf1/cip1) expression (P = 0.003). Neither p53, nor p21(waf1/cip1), nor combinations of expression were independently related to survival when histology, age, stage, and differentiation were considered.

CONCLUSIONS

p53 expression in the absence of p21(waf1/cip1) expression is a better marker of poor prognosis than either p53 or p21(waf1/cip1) expression status alone in univariate analysis. Absence of independent prognostic significance may be related to the paucity of early stage cases in the current study.

Clear cell carcinoma has an expression pattern of cell cycle regulatory molecules that is unique among ovarian adenocarcinomas

BACKGROUND

The purpose of this study was to identify biologic differences between ovarian clear cell carcinoma and other ovarian adenocarcinomas by comparing the expression of cell cycle regulatory molecules and by analyzing the survival of the patients.

METHODS

In 51 cases of epithelial ovarian carcinoma, the expression of the cell proliferation marker Ki-67 and that of the cell cycle regulatory molecules p53, p16, p21, p27, cyclin E, and cyclin A was studied using immunohistochemical techniques. The correlations among clinical stage, histologic subtype, labeling index for Ki-67, and expression of these cell cycle regulators were examined statistically. Multivariate survival analysis was performed using these factors in the Cox proportional hazards model.

RESULTS

Clear cell carcinoma revealed such trends as low expression of both p53 and cyclin A and significantly increased expression of both p21 and cyclin E (compared with the other histologic subtypes). In all ovarian carcinomas, a very strong positive correlation (correlation coefficient 0.79; P < 0.0001) between p53 positive staining and cyclin A positive staining and a weak positive correlation (correlation coefficient 0.47; P < 0.01) between p21 positive staining and cyclin E positive staining were recognized at the level of expression of cell cycle regulatory molecules. Clinical stage was the only independent predictive factor for the survival of the patients.

CONCLUSIONS

Among ovarian adenocarcinomas, clear cell carcinoma exhibits a unique pattern of expression of cell cycle regulatory molecules, though in this study the survival of the patients did not correlate with histologic subtype, only with clinical stage.

Immunophenotype of ovarian cancer as predictor of clinical outcome: evaluation at primary surgery and second-look procedure

OBJECTIVE

This study was undertaken to evaluate whether immunophenotyping of advanced epithelial ovarian cancer could predict response to initial chemotherapy and whether tumor immunophenotype changed after chemotherapy.

STUDY DESIGN

Fifty-four patients with stage III and IV ovarian cancer, treated at the University of Washington Medical Center, had pathology specimens evaluated. A subset of 23 patients also had specimens from a secondary surgery evaluated. Using immunocytochemistry, tumors were immunostained for overexpression of c-erb-B-2, epidermal growth factor receptor (EGFR), p53, and expression of the Ki67-defined antigen (a marker of cellular proliferation), tumor necrosis factor alpha (TNFalpha), estrogen receptor (ER), progesterone receptor (PR), and P-glycoprotein (P170, a marker of multidrug resistance). Twenty-four patients had a good response to chemotherapy (defined as a negative, or microscopically positive second look), and 30 had a poor response (defined as grossly positive second look or progressive disease).

RESULTS

Comparison of tumor markers from the initial and the secondary surgeries revealed that the only significant change was in the Ki67-defined cell proliferation rate, which showed a marked reduction in those with a good response to chemotherapy (P = 0.002). Comparison of tumor markers at initial surgery between good and poor responders revealed a correlation with p53 expression. Good responders were less likely to have p53 overexpression compared to poor responders, and this result approached significance (P = 0.058). Comparison of tumor markers at secondary surgery revealed a significant reduction in Ki67-defined cell proliferation rate in good responders compared to poor responders (P = 0.01). No significant differences were found between good and poor responders for the other tumor markers evaluated.

CONCLUSIONS

The only tumor markers to predict for response to chemotherapy were p53 at initial surgery (P = 0.058) and Ki67 indices at secondary surgery (P = 0.001). Expression of steroid hormone receptors, TNFalpha, and P-glycoprotein and overexpression of c-erb-B-2 or EGFR are not associated with chemoresistance.

Correlation of TP53 mutations and p53 expression in ovarian tumors

To characterize the involvement of the TP53 tumor suppressor gene in ovarian cancer, mutation analysis of exons 2-11 of TP53 and immunodetection of its protein product, p53, were done in 48 ovarian tumors. Normally, p53 is not immunodetectable. Missense TP53 mutations have been reported to result in p53 accumulation and detection, but mutations generating premature stop codons have not. Mutations were identified in 19 of 41 malignant tumors but not in 5 benign tumors and 2 tumors of low malignant potential. Fifteen of the 19 tumors with mutations also stained positively by immunohistochemistry or Western blot or both. They included 11 missense mutations, 1 in-frame duplication (474ins6), and 3 frameshift mutations generating premature stop codons. The three tumors with frameshifts also had a wild-type TP53 allele and displayed normal size but not truncated p53 by Western blot. This indicates that these tumors express wild-type p53. The significance of TP53 mutations in the development of the three tumors is questionable unless there is a mechanism for inactivating wild-type p53. Nine of the 19 mutations found here, including the 3 frameshifts, were previously not reported in ovarian cancer. Thirteen of the 19 mutations were single nucleotide substitutions with 6 transitions and 7 transversions. The ratio of transversions to transitions (1.2) was different from literature reports (0.5) (P < 0.01). Thus, the spectrum of TP53 mutations in our study differed from other ovarian tumor reports. This difference may be due to population-based differences in the molecular epidemiology of TP53 mutations.

Loss of heterozygosity on chromosome 6q27 and p53 mutations in epithelial ovarian cancer

Loss of heterozygosity (LOH) in chromosome region 6q27 and p53 mutations were studied to attempt to clarify the genetic etiology of ovarian cancer, with particular reference to clear cell adenocarcinoma (CCC), which has a poor prognosis. 6q27 LOH in 70 epithelial ovarian cancer patients was examined using four restriction fragment length polymorphism markers located at 6q27; p53 mutations in tumor DNA were detected using polymerase chain reaction single-strand conformation polymorphism and sequencing. 6q27 LOH was confirmed in 26 of 48 informative cases (54.2%). No differences in the incidence of 6q27 LOH were seen by histologic type; 6q27 LOH was observed in 45% (5/11) of CCCs. p53 mutations were detected in 19 of the 48 tumors (39.6%), but in only one (9%) CCC. These results suggest that a putative tumor suppressor gene involved in the onset of epithelial ovarian cancer is located at 6q27. This gene is one of the keys to clarifying the genetic etiology of epithelial ovarian cancer and particularly CCC, given the low incidence of p53 mutations in this tumor type.

Association of loss of heterozygosity at the p53 locus with chemoresistance in osteosarcomas

Although the osteosarcoma is considered to be among the most chemosensitive malignancies and preoperative chemotherapy is commonly applied, an appreciable proportion of cases are in fact quite sensitive. Predictive markers for chemosensitivity are therefore desirable in order to develop effective treatment strategies. Thirty-two cases of conventional osteosarcomas treated at the Cancer Institute Hospital, Tokyo, were analyzed. The sensitivity to preoperative chemotherapy was investigated with reference to loss of heterozygosity (LOH) at the 17p13 (p53) and 13q14 (Rb) loci and expression of the cell-cycle associated proteins, p53, Rb, p21/Waf-1, mdm-2 and Ki-67, as detected immunohistochemically. LOH was detected by analyzing polymerase chain reaction products at marker microsatellite loci. The efficacy of chemotherapy was evaluated both radiologically and histologically. LOH at p53 or Rb loci was seen in 54% (13/24) and 58% (14/24) of cases, respectively. Only 15% of osteosarcomas with LOH at the p53 locus were sensitive to preoperative chemotherapy, as compared to 64% of tumors without such loss (P < 0.05). A similar but much less distinct tendency was observed with LOH at the Rb locus. No relationship was evident between chemosensitivity and immunohistochemical staining patterns for p53, Rb, p21/Waf-1, mdm-2 or Ki-67. The results suggest that p53 gene deletion, but not the other parameters investigated, may be useful for predicting chemoresistance of osteosarcomas.

Drug resistance in ovarian cancer - the role of p53

The aims were to determine the importance of p53 and bcl-2 expression on the response to chemotherapy with alkylating agents in patients with ovarian cancer. We have followed the response to chemotherapy in a series of 59 patients with ovarian adenocarcinoma designated as p53 and bcl-2 positive or negative by immunocytochemistry. Of these cases, 50 received either cisplatin + treosulfan or treosulfan alone. Immunocytochemistry for p53 was positive in 28/59 tumors. Patients were grouped according to their response to chemotherapy (stable or progressive disease) assessed at 6, 12, and 18 months. There was increasing divergence of p53+ and p53- tumors over time. Of those which were p53+, 25% showed progression at 6 months, 80% at 12 months and 89% progression at 18 months. In contrast, 23%, 50%, and 67% of p53- tumors showed progression at 6, 12 and 18 months respectively. For bcl-2, in 23/55 positive tumors there was progression in 35%, 78% and 94% compared with 25%, 57% and 59% in bcl-2 negative tumors at 6,12 and 18 months respectively. Those tumors which were bcl-2 and p53 negative were most likely to progress, while those which were bcl-2 and p53 positive had the best prognosis. These differences did not translate into increased overall survival with minimum follow-up of 12 months. This data lends support to our suggestion that despite initially increased susceptibility to alkylating agents, enhanced genomic instability due to p53 inactivation may render tumors more likely to develop resistance to chemotherapy over time. This effect may be altered by bcl-2 function, lack of which will lead to a good response to chemotherapy as the tumor's ability to undergo apoptosis will not be compromised.

TP53 mutation in ovarian carcinoma

This short report describes the detection of mutations of the TP53 tumour suppressor gene in sporadic ovarian carcinomas using archival paraffin-embedded tissues and automated fluorescent DNA sequencing. TP53 mutations were detected in eight tumours. Missense mutations predominated and all were transitions. Mutations were commonest in late-stage serous tumours. In three cases, where tissue was available, the mutations were homogeneous throughout several sections of the bilateral ovarian tumours and in omental metastases. These data confirm the findings of previous investigations describing TP53 mutation in ovarian carcinoma and demonstrate that archival paraffin-embedded tissues can be used for such analyses.

WAF1 expression and p53 mutations in human colorectal cancers

The expression of the WAF1 gene was examined in the tissues of primary colorectal cancers and of adjacent non-neoplastic mucosas by Western blot analysis. p53 mutations of these cancer tissues were also analyzed by the polymerase chain reaction/single-strand conformation polymorphism followed by direct sequencing. Missense mutations of p53 were recognized in 19 out of 40 cases. Five cancers (12.5%) displayed much lower expression of WAF1 than did their corresponding mucosas, and all of them contained mutant p53. Fourteen cancers (35%) expressed the same level of WAF1 as their mucosas, and 5 of them had mutant p53. Twenty-one cancers (52.5%) had much higher WAF1 expression than their mucosas, and 9 of them had mutant p53. When Duke's classification was applied to these colorectal cancers, it was found that the cancers with reduced expression of WAF1 basically coincided with late (C or D) stages (4 out of 5 cases), while the cancers with higher WAF1 expression were consistent with early (A or B) stages (17 out of 21 cases). Down-regulation of WAF1 in colorectal cancer tissues may be implicated in tumor progression.

p53 alterations are predictive of chemoresistance and aggressiveness in ovarian carcinomas: a molecular and immunohistochemical study

Chemotherapeutic management of ovarian cancers is a difficult task as these neoplasms show significant differences in chemosensitivity, even if they share identical clinicopathological features. The present study was undertaken to investigate the prognostic and predictive role of p53 alterations in ovarian cancer. To this end, using different technical approaches, i.e. genetic and immunohistochemical analyses, we analysed a series of 68 ovarian neoplasms including 15 low malignant potential (LMP) tumours and 53 invasive carcinomas. We never observed p53 abnormalities in LMP tumours. p53 alterations were present only in invasive ovarian carcinomas, and they were detected much more frequently in tumours characterized by high histological grade (P = 0.01) and advanced-stage disease (P = 0.006 and P = 0.05 for gene mutations and protein expression respectively). For 33 patients with invasive ovarian cancer, information was available concerning response to cisplatin-based chemotherapy. A strong correlation (P = 0.001) has emerged between p53 alterations and response to chemotherapy; only one (14%) of seven patients who had a pathological complete response to antiblastic drugs showed p53 aberrations, whereas 18 (82%) of 22 cases with partial response and all of the four non-responsive patients scored positive for p53 abnormalities. We also observed that patients with p53 mutations had a significantly shorter progression-free survival than patients with p53-negative tumours (P = 0.05). Taken together, our results strongly suggest that in epithelial ovarian malignancies tumours showing p53 aberrations are significantly less sensitive to chemotherapy and more aggressive than those with functional p53. Thus, a routine analysis of this gene could have profound implications for the treatment of ovarian cancer.

TP53 mutation analyses on breast carcinomas: a study of paraffin-embedded archival material

The aim of this investigation was to examine the possibility of analysing TP53 mutations in archival paraffin-embedded material with the constant denaturant gel electrophoresis (CDGE) method. We extracted DNA from 193 archival primary breast carcinoma samples, diagnosed in 1981-83; further analysis was possible for 186 of these. TP53 mutations in exons 5-8 were detected with CDGE in 30 samples (16.1%) and 17 of these mutations were confirmed by sequencing. Immunohistochemistry demonstrated TP53 nuclear accumulation in 58 tumours (31%). A strong association between the presence of TP53 mutations and TP53 immunostaining was observed (P < 0.001). Our mutation and immunohistochemistry results are in agreement with other findings based on fresh tumour tissue. TP53 abnormalities were significantly related to high S-phase fraction, low oestrogen receptor (ER) content and high tumour grade. Survival of patients with TP53 abnormalities, in the group as a whole, did not differ from patients with normal TP53. Our study did, however, show that patients with abnormal TP53 had a significantly shorter post-recurrence survival (P = 0.005) than patients with normal TP53.

p53 mutation, allele loss on chromosome 17p, and DNA content in ovarian carcinoma

The aim of this investigation was to explore the relationships between p53 mutation, DNA aneuploidy, 17p deletions, and clinical stage in ovarian cancer. Nuclear suspensions were obtained by tissue disaggregation, stained with propidium iodide, and analysed on a Coulter EPICS Elite flow cytometer. DNA cell cycle analysis was performed using Multicycle software (Phoenix Flow Systems). DNA extracted from paraffin-embedded archival carcinomas/non-tumour tissue was used as template for PCR amplification of the microsatellite dinucleotide repeat polymorphism D17S513, a locus telomeric to p53 on 17p13.1. Allele loss at D17S513 was detected in 64.5 per cent of carcinomas (20 of 31 informative cases). DNA aneuploidy was detected in 20 of 54 (37 per cent) carcinomas. Eight of ten cases previously shown to harbour p53 mutations showed aneuploid DNA content. Although ten other DNA aneuploid cases had shown no p53 mutations, the results show a statistically significant association between p53 mutation and DNA aneuploidy (P < 0.01). Furthermore, the mean DNA index of the DNA aneuploid cases was significantly higher in p53 mutant cases compared with those showing no p53 mutation (P = 0.02). There was also a significant association between p53 mutations and stage, between ploidy and stage, and between allelic deletions at D17S513 or p53 and stage, but not between these allelic deletions and ploidy. p53 mutations appear to be associated with DNA aneuploidy in ovarian cancer independently of 17p deletions. p53 mutations, DNA aneuploidy, and 17p deletions are associated with late stage.

Molecular oncology in pancreatic cancer

Cancer of the pancreas still has a very poor prognosis despite improved diagnostic methods and therapeutic regimens. The reasons for the aggressiveness of this cancer are not known, and the molecular mechanisms that govern the growth of pancreatic cancer cells are still not clearly defined. During the past two decades the development of new molecular biological techniques has offered new perspectives for a better understanding of pancreatic cancer. Tumor markers such as CA19-9 and CEA are used for diagnosis and for following the postoperative course of cancer patients. Characterization of pancreatic cancer cells using several molecular biological techniques has revealed overexpression or altered expression of growth factors and adhesion molecules, implying altered cell-cell and growth-regulatory interactions. In pancreatic cancer mutations in oncogenes and tumor suppressor genes are frequently detected in p53 and K-ras. This article reviews the possible molecular approaches for diagnosis, prognosis, or even therapy of pancreatic cancer.

Rare occurrence of p53 and ras gene mutations in preneoplastic and neoplastic mouse endometrial lesions induced by N-methyl-N-nitrosourea and 17 beta-estradiol

To examine K-, H-, or N-ras and p53 gene mutations in mouse endometrial carcinogenesis induced by N-methyl-N-nitrosourea and 17 beta-estradiol, we performed polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) in 13 adenocarcinomas and 11 other preneoplastic lesions. A significant shifted band in exon 5 of p53 using PCR-SSCP was detected in one of 13 adenocarcinomas. Direct sequencing showed that the mutation was TCA-to-TGA (Ser-to-End) transition. These results suggest that ras gene mutations were not related to carcinogenesis and inactivation of p53 may occur with low frequency during the mouse endometrial carcinogenesis in this model.