Spontaneous apoptosis in ovarian carcinomas: a positive association with p53 gene mutation is dependent on growth fraction

Prognosis of patients with BRCA1-associated ovarian carcinomas depends on TP53 accumulation status in tumor cells

OBJECTIVE

TP53 mutation is the most frequent molecular event in BRCA1-associated ovarian carcinomas. TP53 status may be a confounding factor in the evaluation of clinical importance of other proteins. We aimed to evaluate the clinical significance of BRCA1 mutations with respect to the TP53 accumulation status in 159 high-grade ovarian carcinomas.

METHODS

Statistical analyses were done with the Kaplan-Meier method, log-rank test, the Cox's and logistic regression models for all patients, and in subgroups with and without TP53 accumulation (TP53+ and TP53-, respectively).

RESULTS

Forty of 159 ovarian carcinomas (25.2%) were diagnosed in patients with BRCA1 germline mutations; 102 tumors (64.2%) were TP53+ and 57 (37.8%) were TP53-. Among patients with TP53+ carcinomas, BRCA1 carriers had increased odds of recurrence compared with sporadic cases (HR 2.25, P=0.003; median disease-free survival time 7.7 vs. 18.4months, respectively). In the smaller TP53- subgroup, BRCA1 mutation reduced the risk of death by 46% (HR 0.54, P=0.099, median overall survival time 42.7 vs. 28.1months), but beyond the border of significance. When the TP53 status was not taken into account, BRCA1 mutations did not show any significance, however, there was a trend toward increased odds of complete remission for women with BRCA1 mutations compared to non-carriers (OR 2.47, P=0.064). Taxane-platinum therapy showed advantage over the platinum-cyclophosphamide one in the entire group of patients and in the TP53+ subgroup.

CONCLUSIONS

Our results suggest that the TP53 accumulation status determines the prognosis of BRCA1 mutation carriers with high-grade ovarian carcinomas.

Effects of trifluralin on the mouse ovary

Trifluralin, a herbicide used to protect many arable and horticultural crops, was evaluated for its potential toxicity on the mammalian ovary. To this end, adult female mice were fed or not (control) with a trifluralin-enriched diet (150 mg/kg body weight/day) during gestation and lactation. After weaning, 3-week-old female mice from either trifluralin-treated or control groups were used to evaluate whether the exposure to this herbicide in utero and during lactation could induce stress responses in the ovary. It was found that trifluralin exposure caused a significantly higher level of p53, but not of pRb, in the whole ovary, and in particular in granulosa cells. TUNEL staining showed that herbicide treatment did not increase the apoptotic index of the somatic compartment. Also oocyte fertilizability was unaffected, as metaphase II oocytes retrieved from treated mice were capable of forming male and female pronuclei after in vitro fertilization as control mice. However, trifluralin determined a slightly higher number of oocytes with cytoplasmic degeneration compared with control animals. In conclusion, our results suggest that exposure to a low trifluralin dose during pregnancy and lactation does not impair oocyte quality, but can induce a stress response in ovarian somatic cells.

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.

Spontaneous regression in recurrent epithelial ovarian cancer

BACKGROUND

Although spontaneous regression has been reported in several cancers, it is generally believed that this rare phenomenon does not occur in epithelial ovarian cancer.

CASE

We presented a stage IV epithelial ovarian cancer patient with long-term disease-free survival after palliative local irradiation alone against recurrence. The recurrent supraclavicular lymph node was almost completely necrotic, and the swelling of the para-aortic lymph node spontaneously regressed.

CONCLUSION

The histologic features and unexpected clinical course in this patient strongly suggest that spontaneous regression occurred in recurrent epithelial ovarian cancer.

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.

TP53 status determines clinical significance of ERBB2 expression in ovarian cancer

ERBB2 expression has been found in 19 to 44% of ovarian carcinomas; however, its predictive value has not been demonstrated, and trastuzumab has not found clinical application in ovarian cancer patients. We evaluated clinical significance of ERBB2 expression in relation to TP53 accumulation in ovarian carcinoma patients treated with platinum-based regimens. Immunohistochemical analysis with CB11 and a novel NCL-CBE356 antibody (against the internal and external domains of ERBB2, respectively) was performed on 233 tumours (FIGO stage IIB—IV); the US Food and Drug Administration-approved grading system with 0 to 3+ scale was used for evaluation, and the results were analysed by the Cox and logistic regression models. In all, 42% of the tumours expressed (category 1+, 2+ or 3+) either CB11 or CBE356 or both (CB11/CBE356 parameter). Associations between ERBB2 expression and clinical factors were observed only if tumours with staining category 1+ were grouped together with tumours showing staining categories 2+ and 3+. CB11/CBE356 parameter had a better predictive value than CB11 alone. CB11/CBE356 expression was negatively associated with platinum sensitivity (PS) in the TP53(−) group (P=0.022) and with disease-free survival (DFS) in the TP53(+) group (P=0.009). Our results may suggest that trastuzumab should be given postoperatively to patients with TP53(−)/ERBB2(+) ovarian carcinomas to enhance PS, and after completion of chemotherapy to patients with complete remission and TP53(+)/ERBB2(+) carcinomas to extend DFS time (in total to 30.4% of all patients analysed). Thus, novel criteria for ovarian cancer patient inclusion for clinical trials with trastuzumab should be considered and tested.

P21WAF1, P27KIP1, TP53 and C-MYC analysis in 204 ovarian carcinomas treated with platinum-based regimens

BACKGROUND

The prognostic and predictive value of cell cycle regulatory proteins in ovarian cancer has not been established. We evaluated the clinical and biological significance of P21(WAF1), P27(KIP1), C-MYC, TP53 and Ki67 expressions in ovarian cancer patients.

MATERIALS AND METHODS

Immunohistochemical analysis was performed on 204 ovarian carcinomas of International Federation of Gynecology and Obstetrics (FIGO) stage IIB to IV treated with platinum-based chemotherapy. Multivariate analysis with Cox and logistic regression models was performed in the whole group, and in the TP53-negative and TP53-positive subgroups.

RESULTS

High P21(WAF1) labeling index (LI) was an independent positive predictor of platinum-sensitive response (P = 0.02). Overall survival was positively influenced by P21(WAF1) LI (P = 0.02) or by P21(WAF1) plus P27(KIP1) LI (P = 0.004) in the TP53-negative group only. Ki67 LI showed borderline association with disease-free survival (P = 0.05). Growth fraction was negatively associated with P21(WAF1) and P27(KIP1) indices in the TP53-negative group (P = 0.023 and 0.008, respectively), and these associations were borderline or lost in the TP53-positive group. Endometrioid and clear cell carcinomas differed from other carcinomas by having a low incidence of TP53 accumulation, a high incidence of C-MYC overexpression (70%) and a low median Ki67 LI (all with P <0.001).

CONCLUSIONS

We have shown an independent predictive value of P21(WAF1) LI in ovarian carcinoma patients. The prognostic value of P21(WAF1) and P21(WAF1) plus P27(KIP1) LI was determined by TP53 status. A high frequency of C-MYC overexpression in endometrioid and clear cell carcinomas may suggest its role in the development of these tumor types.

Evaluation of clinical significance of TP53, BCL-2, BAX and MEK1 expression in 229 ovarian carcinomas treated with platinum-based regimen

In cell line studies, BCL-2, BAX, as well as novel MEK1 protein levels have strong influence on ovarian cancer response to cisplatin-based chemotherapy. However, such associations have not been demonstrated clinically. We evaluated prognostic/predictive significance of these proteins with regard to TP53 status. Immunohistochemical analysis was performed on 229 ovarian carcinomas FIGO stage IIB-IV treated with platinum-based chemotherapy; the results were analysed by the Cox and logistic regression models. Clinical parameters (residual tumour size, patient age, FIGO stage) were the only indicators of overall survival (OS) and the strongest predictors of complete remission (CR). On the other hand, BAX expression was the strongest (P=0.005) or the only (in FIGO IIIC, P=0.02) prognostic indicator of disease-free survival (DFS) in the TP53(+) group. TP53(+) and TP53(-) ovarian carcinomas differed in clinical and molecular prognostic and predictive factors. Another novel finding is that CR was negatively influenced by high BAX expression in all patients group (P=0.047) and by BCL2 expression in the TP53(-) group (P=0.05). High MEK1 expression was associated with endometrioid and clear cell carcinomas (P=0.049); its loss was found with advancing FIGO stage (P=0.002). Our results suggest that binomial TP53 status divides ovarian carcinomas into two biologically distinct groups. BAX expression is an important factor of DFS in the TP53(+) group. BCL-2 and BAX, but not MEK1 expressions have predictive value in ovarian cancer patients treated with platinum-based chemotherapy.

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.

Spontaneous and inducible apoptosis in oesophageal adenocarcinoma

The use of neoadjuvant chemoradiotherapy prior to surgery in the treatment of oesophageal adenocarcinoma has increased in recent years, and up to 25% of patients will have a complete pathological response to the neoadjuvant therapy. Many patients will not respond, however, and the knowledge of molecular factors predicting response or resistance to chemoradiotherapy is required to enhance treatment results. An understanding of apoptosis and cell proliferation may be relevant and this study focused on apoptotic indices and cell-cycle related (Ki-67, p53 and bcl-2) protein expression in a cohort of 42 patients with primary oesophageal adenocarcinoma. We documented that apoptosis occurs among viable (proliferating) tumour cells in all adenocarcinoma cases examined in this study. Pre-operative chemoradiotherapy significantly increased apoptosis and significantly decreased cell proliferation (estimated by Ki-67 expression). Immunohistochemically detected p53 and bcl-2 gene products had no regulatory role in the apoptotic process. The cumulative expression of p53 protein is significantly associated with increasing proliferation activity. Evaluation of apoptosis in pre-treatment specimens may have potential utility in predicting the efficacy of treatment. Assessment of the tumours proliferation activity by Ki-67 expression might identify patients who are at risk of developing metastatic disease.

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.