Biomarker-based early detection of epithelial ovarian cancer based on a five-protein signature in patient's plasma - a prospective trial.

BACKGROUND: Trial on five plasma biomarkers (CA125, HE4, OPN, leptin, prolactin) and their possible role in differentiating benign from malignant ovarian tumors. METHODS: In this unicentric prospective trial preoperative blood samples of 43 women with ovarian masses determined for ovarian surgery were analyzed. 25 patients had pathologically confirmed benign, 18 malignant ovarian tumors. Blood plasma was analyzed for CA125, HE4, OPN, leptin, prolactin and MIF by multiplex immunoassay analysis. Each single protein and a logistical regression model including all the listed proteins were tested as preoperative predictive marker for suspect ovarian masses. RESULTS: Plasma CA125 was confirmed as a highly accurate tumor marker in ovarian cancer. HE4, OPN, leptin and prolactin plasma levels differed significantly between benign and malignant ovarian masses. With a logistical regression model a formula including CA125, HE4, OPN, leptin and prolactin was developed to predict malignant ovarian tumors. With a discriminatory AUC of 0.96 it showed to be a highly sensitive and specific diagnostic test for a malignant ovarian tumor. CONCLUSIONS: The calculated formula with the combination of CA125, HE4, OPN, leptin and prolactin plasma levels surpasses each single marker in its diagnostic value to discriminate between benign and malignant ovarian tumors. The formula, applied to our patient population was highly accurate but should be validated in a larger cohort. TRIAL REGISTRATION: Clinical Trials.gov under NCT01763125 , registered Jan. 8, 2013.

Statistical controversies in clinical research: the importance of importance.

We define the notion of 'importance' of prognostic factors in studies of survival and suggest quantifying it by the Schemper-Henderson measure of explained variation. Conceptual differences to the standard approach for the statistical analysis of oncologic studies of survival are discussed and exemplified by means of a study of ovarian cancer. Explained variation permits to establish a ranking of the importance of factors, also if measured on different scales, or of different types (dichotomous, qualitative or continuous), and permits to compare groups of related factors. In practice, the importance of prognostic factors often is disappointingly low. From this, it follows that even strong and highly significant prognostic factors often do not translate into close determination of individual survival of patients.

Biclustering strategies for genetic marker selection in gynecologic tumor cell lines.

Over the past few decades great interest has been focused on cell lines derived from tumors, because of their usability as models to understand the biology of cancer. At the same time, advanced technologies such as DNA-microarrays have been broadly used to study the expression level of thousands of genes in primary tumors or cancer cell lines in a single experiment. Results from microarray analysis approaches have provided valuable insights into the underlying biology and proven useful for tumor classification, prognostication and prediction. Our approach utilizes biclustering methods for the discovery of genes with coherent expression across a subset of conditions (cell lines of a tumor type). More specifically, we present a novel modification on Cheng & Church's algorithm that searches for differences across the studied conditions, but also enforces consistent intensity characteristics of each cluster within each condition. The application of this approach on a gynecologic panel of cell lines succeeds to derive discriminant groups of compact bi-clusters across four types of tumor cell lines. In this form, the proposed approach is proven efficient for the derivation of tumor-specific markers.

BRCA1 gene promoter methylation status in high-grade serous ovarian cancer patients--a study of the tumour Bank ovarian cancer (TOC) and ovarian cancer diagnosis consortium (OVCAD).

BACKGROUND: Mutations in BRCA1/2 genes are involved in the pathogenesis of breast and ovarian cancer. Inactivation of these genes can also be mediated by hypermethylation of CpGs in the promoter regions. Aim of this study was to analyse the clinical impact of BRCA1 promoter gene methylation status in a homogenous cohort of high-grade serous ovarian cancer (HGSOC) patients. METHODS: The cohort included 257 primary HGSOC patients treated by cytoreduction and platinum-based chemotherapy. DNA was extracted from fresh frozen tissue samples. BRCA1 gene promoter methylation rate was assessed using polymerase chain reaction (PCR). RESULTS: 14.8% of patients presented hypermethylation within a selected region of the BRCA1 promoter. The rate of hypermethylation was significantly higher in younger patients (20.8% hypermethylation in the age group ⩽ 58 years versus 8.7% hypermethylation in the age group >58 years; p = 0.008). Optimal tumour debulking could be reached in 63% of patients, without significant differences in the extent of residual disease with respect to the methylation status. No impact of BRCA1 gene promoter methylation status on progression free- and overall-survival rates was found. No significant differences within BRCA1 promoter methylation status between primary and metastatic tissue could be observed. These results on BRCA1 promoter methylation status were also confirmed in a subgroup of 107 patients found negative for BRCA1 exon 11 mutations. CONCLUSIONS: Our data suggest that BRCA1 methylation determines the earlier onset of HGSOC. Furthermore our study supports the idea that BRCAness is not only due to mutations but also to epigenetic changes in BRCA1 promoter gene.

eNOSI4 and EPHX1 polymorphisms affect maternal susceptibility to preeclampsia: analysis of five polymorphisms predisposing to cardiovascular disease in 279 Caucasian and 241 African women.

PURPOSE: The aim of this study was to evaluate possible associations of genetic polymorphisms predisposing to cardiovascular disease with the development and/or the severity of preeclampsia. METHODS: A two hospital-based prospective case-control study was performed in Germany and Ghana. 470 blood samples of 250 Caucasian and 220 black African have been genotyped by pyrosequencing and fragment length analysis. We evaluated the distribution of the epoxide hydrolase 1 (EPHX1) polymorphism on exon 3, the endothelial nitric oxide synthase (eNOS) polymorphisms on exon 7 and on intron 4, the angiotensinogen polymorphism on exon 2 and the estrogen receptor 1 polymorphism in intron 1. RESULTS: 74 Caucasian and 84 African were classified as preeclampsia with 27 Caucasian developing a hemolysis, elevated liver enzymes and low platelets (HELLP) syndrome and 17 African women experiencing eclampsia. Multivariate logistic regression analysis adjusting for ethnicity, age and parity revealed for carriers of eNOSI4 VNTR4a a 1.7-fold increased (95% CI 1.10-2.711, p = 0.016) risk to develop preeclampsia and a 3.6-fold increase for carriers of the EPHX1 113Tyr (95% CI 1.366-8.750, p = 0.009) to develop severest preeclampsia. CONCLUSION: Our finding of eNOSI4 polymorphism predisposing to preeclampsia independently of ethnicity, age and parity supports the concept of NO being involved in the endothelial disorder preeclampsia. Since EPHX1 is highly expressed in the liver, can interact with various signaling pathways and is involved in central nervous system disorders, the association of EPHX1 polymorphism with the HELLP syndrome and eclampsia may hint to EPHX being a further key player in the pathogenesis of preeclampsia.

The time interval from surgery to start of chemotherapy significantly impacts prognosis in patients with advanced serous ovarian carcinoma - analysis of patient data in the prospective OVCAD study.

OBJECTIVE: Cytoreductive surgery and platinum-based systemic therapy constitute the standard treatment of patients with advanced ovarian cancer. The aim of the present study was to evaluate whether the time interval from surgery to start of chemotherapy has an impact on clinical outcome. METHODS: Data of 191 patients with advanced serous (FIGO III-IV) ovarian cancer from the prospective multicenter study OVCAD (OVarian CAncer Diagnosis) were analyzed. All patients underwent primary surgery followed by platinum-based chemotherapy. RESULTS: The 25%, 50%, and 75% quartiles of intervals from surgery to start of chemotherapy were 22, 28, and 38 days, respectively (range, 4-158 days). Preoperative performance status (P<0.001), extent of surgery (P<0.001), and perioperative complications (P<0.001) correlated with intervals from surgery to initiation of chemotherapy. Timing of cytotoxic treatment [≤ 28 days versus >28 days; hazard ratio (HR) 1.73 (95% confidence interval 1.08-2.78), P=0.022], residual disease [HR 2.95 (95% confidence interval 1.87-4.67), P<0.001], and FIGO stage [HR 2.26 (95% confidence interval 1.41-3.64), P=0.001] were significant prognostic factors for overall survival in multivariate analysis. While the interval from surgery to start of chemotherapy did not possess prognostic significance in patients without postoperative residual disease (n=121), it significantly correlated with overall survival in patients with postoperative residual disease [n=70, HR 2.24 (95% confidence interval 1.08-4.66), P=0.031]. CONCLUSION: Our findings suggest that delayed initiation of chemotherapy might compromise overall survival in patients with advanced serous ovarian cancer, especially when suboptimally debulked.

Preoperative HE4 expression in plasma predicts surgical outcome in primary ovarian cancer patients: results from the OVCAD study.

OBJECTIVES: Epithelial ovarian cancer (EOC) is the major cause of death due to gynecological malignancies. The most important prognostic factors are residual tumor mass after surgery and platinum-response. No predictive biomarkers are available to identify patients who will benefit from standard treatment. The aim of our study was to analyze the role of HE4 in predicting surgical and clinical outcome in primary EOC. METHODS: In the European multicentric project "OVCAD", 275 consecutive patients with primary EOC were enrolled. Patients were eligible if radical cytoreductive surgery was performed and platinum-based chemotherapy was applied. Plasma and ascites samples were collected before or during surgery. The concentrations of HE4 and CA125 was determined using ELISA and Luminex technique, respectively. RESULTS: Median age at first diagnosis was 58 years (range 18-85 years). Most patients presented with advanced stage disease, FIGO III or IV (94.6%), grades II-III (96%) and serous histology (86.2%). In most cases a complete cytoreduction to no residual tumor mass was achieved (68.4%). Higher plasma HE4 levels correlated with poor surgery outcome in terms of macroscopically residual tumor mass (p<0.001) and platinum-resistance (p=0.009). Plasma CA125 and the risk index (HE4 and CA125) were independent predictive factors for surgical outcome (p=0.001, OR=3.37, 95% CI=1.61-7.06 and p<0.001, OR=6,041, 95% CI=2.33-15.65, respectively). FIGO stage III was an independent predictive factor for platinum response (p=0.039, OR=0.436, 95% CI=0.198-0.960). CONCLUSIONS: The presented data are showing that the combination of HE4 and CA125 expression in plasma might predict the surgical outcome in EOC and by this may have a prognostic impact on PFS and OS.

Prognostic significance of L1CAM in ovarian cancer and its role in constitutive NF-κB activation.

BACKGROUND: Overexpression of L1-cell adhesion molecule (L1CAM) has been observed for various carcinomas and correlates with poor prognosis and late-stage disease. In vitro, L1CAM enhances proliferation, cell migration, adhesion and chemoresistance. We tested L1CAM and interleukin-1 beta (IL-1ß) expression in tumor samples and ascitic fluid from ovarian carcinoma patients to examine its role as a prognostic marker. PATIENTS AND METHODS: We investigated tumor samples and ascitic fluid from 232 serous ovarian carcinoma patients for L1CAM by enzyme-linked immunosorbent assay. L1CAM expression was correlated with pathoclinical parameters and patients' outcome. IL-1ß levels were measured in tumor cell lysates. Ovarian cancer cell lines were analyzed for the contribution of L1CAM to IL-1ß production and nuclear factor 'kappa-light-chain-enhancer' of activated B-cells (NF-κB) activation. RESULTS: We observed that L1CAM-expressing tumors show a highly invasive phenotype associated with restricted tumor resectability at primary debulking surgery and increased lymphogenic spread. Soluble L1CAM proved to be a marker for poor progression-free survival and chemoresistance. In ovarian carcinoma cell lines, the specific knock-down of L1CAM reduces IL-1ß expression and NF-κB activity. CONCLUSIONS: L1CAM expression contributes to the invasive and metastatic phenotype of serous ovarian carcinoma. L1CAM expression and shedding in the tumor microenvironment could contribute to enhanced invasion and tumor progression through increased IL-1ß production and NF-κB activation.

Δ133p53 is an independent prognostic marker in p53 mutant advanced serous ovarian cancer.

BACKGROUND: We aimed to evaluate the clinical relevance of p53 and p73 isoforms that modulate the function of p53. METHODS: This prospective multicentre study included 154 patients with stage III and IV serous ovarian cancer. A functional yeast-based assay and subsequent sequencing were performed to analyse the p53 mutational status. Expression of p53 and p73 isoforms was determined using RT-qPCR. RESULTS: Δ133p53 expression constituted an independent prognostic marker for recurrence-free (hazard ratio=0.571, P=0.016, 95% CI: 0.362-0.899) and overall survival (hazard ratio=0.365, P=0.004, 95% CI: 0.182-0.731) in patients with p53 mutant ovarian cancer (n=121). High Δ40p53 expression was associated with favourable tumour grading (P=0.037) and improved recurrence-free survival (33.4 vs 19.6 months, P=0.029), but not overall survival (43.1 vs 33.6 months, P=0.139), in patients with p53 wild-type cancer (n=33). Neither the p53 mutational status nor p73 isoform expression possessed prognostic significance in the examined ovarian cancer cases. CONCLUSION: Δ133p53 expression was associated with prognosis in the vast majority of ovarian cancer cases, that is, patients with p53 mutant advanced serous carcinomas. Thus, our findings underline the importance of considering the complex p53 regulatory network.

Alternative splicing of p53 and p73: the novel p53 splice variant p53delta is an independent prognostic marker in ovarian cancer.

Similar to p73, the tumor suppressor gene p53 is subject to alternative splicing. Besides p53DeltaE6 and p53beta, we identified p53zeta, p53delta and p53varepsilon, arising from alternative splicing of exon 6 and intron 9, respectively. p53 splice variants were present in 18 of 34 ovarian cancer cell lines (52.9%) and 134 of 245 primary ovarian cancers (54.7%). p53delta expression was associated with impaired response to primary platinum-based chemotherapy (P=0.032). Also, p53delta expression constituted an independent prognostic marker for recurrence-free and overall survival (hazard ratio 1.854, 95% confidence interval 1.121-3.065, P=0.016; and hazard ratio 1.937, 95% confidence interval 1.177-3.186, P=0.009, respectively). p53beta expression was associated with adverse clinicopathologic markers, that is, serous and poorly differentiated cancers (P=0.002 and P=0.008, respectively), and correlated with worse recurrence-free survival in patients exhibiting functionally active p53 (P=0.049). DeltaN'p73 constituted the main N-terminally truncated p73 isoform and was preferentially found in ovarian cancer cell lines showing functionally active p53, supporting our hypothesis that N-terminally truncated p73 isoforms can alleviate the selection pressure for p53 mutations by the inhibition of p53 protein function.

In ovarian cancer the prognostic influence of HER2/neu is not dependent on the CXCR4/SDF-1 signalling pathway.

HER2/neu overexpression is a driving force in the carcinogenesis of several human cancers. In breast cancer the prognostic influence of HER2/neu was shown to be at least partly based on increased metastatic potential mediated by the chemokine-chemokine receptor pair SDF-1(CXCL12)/CXCR4. We wanted to evaluate the influence of HER2/neu on ovarian cancer prognosis and to investigate whether compromised survival would correlate with CXCR4 expression and/or SDF-1 abundance. Therefore, we analysed HER2/neu, CXCR4, and SDF-1 in 148 ovarian tumour samples by means of immunohistochemistry on tissue microarrays. Overexpression of HER2/neu was found in 27.6% of ovarian cancer tissues and in 15% of ovarian borderline tumours. In ovarian cancer patients, overexpression of HER2/neu correlated closely with overall survival (univariate hazard ratio (HR) 2.59, P=0.005; multiple corrected HR 1.92, P=0.074). In contrast, CXCR4 expression and SDF-1 abundance had no impact on overall survival, and both parameters were not correlated with HER2/neu expression. As expected, cytoplasmic CXCR4 expression and SDF-1 abundance correlated closely (P<0.0001). Our results confirm a univariate influence of HER2/neu expression on overall survival, which was completely independent of the expression of CXCR4 and the abundance of SDF-1, implying significant differences between the HER2/neu downstream pathways in ovarian cancer compared with breast cancer.

Analysis of the human progesterone receptor gene polymorphism progins in Austrian ovarian carcinoma patients.

Ovarian carcinoma is the highest death cause in gynecologic malignancies. Although the molecular basis for familial breast and ovarian cancer is elucidated, few genetic markers have been associated with sporadic ovarian carcinoma. A polymorphism in intron G of the human progesterone receptor (PgR), caused by an Alu insertion, was described to be associated with ovarian carcinoma in a pooled German/Irish population. Later on, a G to T substitution in exon 4, causing a Valine to Leucine change in the hinge region of the receptor, and a synonymous C to T substitution in exon 5 were reported to be linked to the Alu insertion. This complex of the PgR gene polymorphism was designated PROGINS. In order to investigate if PROGINS is associated with risk for ovarian cancer in Austrian women, we analyzed DNA from 226 Austrian patients with sporadic ovarian carcinoma and a control group with 194 healthy volunteers for the PROGINS complex. The PROGINS status was studied in association with risk for ovarian carcinoma, the age of the ovarian patients, the protein level of PgR and estrogen receptor (ER) and histopathological parameters. The results indicate that the frequency of PROGINS carriers in Austrian women is similar to those in women in North America and England. There is no significant difference between the PROGINS allele distribution in ovarian carcinoma patients and healthy women. The PROGINS is not associated with increased risk for ovarian carcinomas. Additionally, the protein levels of ER and PgR were independent of the PROGINS status.

Novel MUC1 splice variants are expressed in cervical carcinoma.

OBJECTIVES: The MUC1 antigen can be used to identify epithelial cells from the background of hemopoietic cells. The present investigation describes patterns of overexpression of two novel MUC1 splice variants in human cervical carcinoma cell lines. METHODS: RT-PCR was carried out to determine MUC1 splice variants in the cervical cancer cell lines C-4 II, C-33A, DoTc 2 4510, C-4 I, SiHa, HT3, Hs 636 T (C4-I), and HeLa. RESULTS: The novel MUC1 splice variant D was expressed in all cell lines and the novel MUC1 splice variant C was expressed in all cell lines but C-33A. Variants A and B were expressed in all (variant A) and all but one (variant B) cell line. MUC1/REP was expressed in all cell lines and MUC1/SEC was positive in all but two cell lines (C-33 A, DoTc 2 4510). All but one cell line (C-33A) expressed MUC1/X and MUC1/Y, and two cell lines (C-33 A, DoTc 2 4510) did not express MUC1/Z, respectively. MUC1 variants A, D, and REP could be demonstrated consistently among all eight cervical carcinoma cell lines we have examined. CONCLUSIONS: The present study describes the feasibility of detecting a large number of MUC1 variants, including MUC1 variants C and D which are described for cervical carcinoma cells for the first time. Further studies will examine the presence of MUC1 splice variants' expression in human cervical carcinoma tissue.

High frequency of allelic imbalance at regions of chromosome arm 8p in ovarian carcinoma.

Progressive genetic changes such as the inactivation of tumor suppressor genes (TSG) are thought to play an important role in the initiation and progression of ovarian cancer. Frequent nonrandom allelic imbalance (AI) at 8p11-p21 and 8p22-pter suggests the existence of TSGs that may be involved in the carcinogenesis of several human malignancies. We investigated 70 ovarian tumors with 11 highly polymorphic markers spanning 8p12-p21 and 8p22-pter to produce an AI map of 8p in epithelial ovarian cancer. Allelic imbalance was demonstrated in 54 tumors (77%), most frequently occurring at D8S136 (54%) and at D8S1992 (55%). Poorly differentiated and advanced stage cancers were more often affected by AI (G1+G2 vs. G3; 20% vs. 66%; stage I+II vs. III+IV, 36% vs. 54%, P<.001; Kruskal-Wallis test) than well differentiated and early stage tumors. There was no relationship between histological subtype and AI. Smallest regions of overlap (SRO) were delineated by analyzing 38 tumors with partial AI. This study provides compelling evidence for the involvement of TSGs on the short arm of chromosome 8, at 8p12-p21 and at 8p23 in the development and progression of epithelial ovarian cancer.

Endothelial nitric oxide synthase gene polymorphism in women with idiopathic recurrent miscarriage.

BACKGROUND: Lack of endothelium-derived nitric oxide is associated with vasospasm and vascular infarction. We investigated the relationship between idiopathic recurrent miscarriage and a polymorphism of the gene encoding endothelial nitric oxide synthase (NOS3). METHOD: In a prospective case-control study, 105 women with idiopathic recurrent miscarriage and 91 healthy controls were investigated. We used the polymerase chain reaction to identify the different alleles of a 27 base pair tandem repeat polymorphism in intron 4 of the NOS3 gene. RESULTS: The wild type B allele was identified on 329 out of 392 chromosomes (frequency 0.84). The polymorphic A allele was present on 63 chromosomes (frequency 0.16). The genotype frequencies were as follows: 68% (B/B), 31% (A/B) and.5% (A/A). The distribution of genotype frequencies was significantly different between the study and control groups for allele A/B heterozygotes (NOS3(A/B)) (36.7 versus 23.8%, P = 0.03, OR 1.6, 95% CI 1.1--3.8). Only one individual was homozygous for the A allele (NOS3(A/A)). She was in the study group. Between women with primary and secondary recurrent miscarriages, no statistically significant difference between the distribution of NOS3(A/B) genotypes (28 versus 34%) was observed. CONCLUSIONS: These data support a role for the NOS3 gene as a genetic determinant of the risk of idiopathic recurrent miscarriage.

Interleukin-8 serum level shift in patients with ovarian carcinoma undergoing paclitaxel-containing chemotherapy.

BACKGROUND: Paclitaxel has been described to induce interleukin-8 (IL-8) transcription and secretion in human ovarian carcinoma cells. The objective of this study was to investigate possible clinical implications of the effect of paclitaxel on IL-8 serum levels in patients suffering from ovarian carcinoma. METHODS: Thirty-one patients with ovarian carcinoma who were treated with combination chemotherapy consisting of paclitaxel and carboplatin entered the study. IL-8 serum levels and CA 125 serum levels were detected three times for each patient directly before chemotherapy, after three cycles of chemotherapy, and after six cycles of chemotherapy. In addition, serum samples from 59 healthy, age-matched women were obtained. A quantitative human IL-8 immunoassay was used to determine the IL-8 serum levels. RESULTS: Seventy-eight percent of patients responded to chemotherapy, with 61% achieving a complete response and 16% achieving a partial response. The median IL-8 serum level before chemotherapy was 75 pg/mL (range, 2.7-903.3 pg/mL), the level during chemotherapy was 23.75 pg/mL (range, 0.5-248.2 pg/mL), and the level after chemotherapy was 17.65 pg/mL (range, 0.6-377.0 pg/mL). The median IL-8 serum level in controls was 15.6 pg/mL (range, 1.4-106.3 pg/mL). The authors found a statistically significant decrease in both IL-8 serum levels (P < 0.05 and P < 0.05) and CA 125 serum levels (P < 0.05 and P < 0.05) from the first to the second measurement and from the first to the third measurement, respectively. They found no correlation between the shifts of IL-8 serum levels and CA 125 serum levels during chemotherapy. CONCLUSIONS: The authors found a significant decrease in IL-8 serum levels in patients undergoing a paclitaxel-containing chemotherapy regimen, indicating that IL-8 possibly acts as a useful monitoring marker in patients with ovarian carcinoma.

p53 polymorphism at codon 72--does it constitute a risk for squamous intraepithelial lesions and invasive cancer of the cervix in Central Europeans?

BACKGROUND: Polymorphisms of the tumour suppresser gene p53 especially at codon 72 are suspected to be associated with an increased risk for malignant transformation. In invasive cervical cancer, the arginine form of the p53 gene is estimated to be more susceptible to degradation mediated by tumour-associated human papilloma viruses (HPV) than the proline form. METHODS: To test the prevalence of p53 polymorphism at codon 72 in 133 healthy women, 50 patients suffering from squamous intraepithelial lesions of the cervix (SIL), and 105 patients with invasive cervical cancer, we developed a polymerase chain reaction (PCR) and microtiter plate-based hybridisation assay. Furthermore, we tested whether the two p53 isoforms increased the risk of developing cervical cancer. RESULTS: The proportions of individual homozygous for arginine, homozygous for proline and heterozygous for arginine and proline in the investigated patient groups did not significantly deviate from the Hardy-Weinberg equilibrium. We found no increased risk of developing cervical cancer in respect to p53 polymorphism, independent of histological diagnosis. DISCUSSION: In conformity with other study groups, our findings do not support the hypothesis that the p53 polymorphism at codon 72 is important in determining an increased risk of developing HPV-associated SIL or invasive cervical cancer in Central Europeans.

p53-dependent radioresistance in ovarian carcinoma cell lines.

In the present study, we investigated the radiosensitivity profiles of three established human ovarian carcinoma cell lines, PA-1, Caov-3, and SK-OV-3, using the adenosine triphosphate-cell viability assay (ATP-CVA). We have correlated radioresponsiveness with the p53 status and the p53 accumulation after irradiation as well as with the Bcl-2 expression and the growth rate of these cell lines. The p53 status was examined by immunocytochemistry and a functional assay (functional analysis of separated alleles in yeast, FASAY); the p53 accumulation was determined by immunocytochemistry and flow cytometry. Furthermore, the Bcl-2 expression before and after irradiation was examined by immunocytochemistry. PA-1, expressing wild-type p53, showed an unequivocal accumulation of p53 protein following exposure to irradiation. This cell line was found to be strongly sensitive to irradiation. The two p53 mutant cell lines Caov-3 and SK-OV-3 showed radioresistance at different degrees and irradiation did not result in p53 accumulation. None of the cell lines examined expressed Bcl-2 protein and no change was seen after irradiation. Furthermore, the most sensitive cell line to irradiation, PA-1, showed the highest proliferative activity, while Caov-3 and SK-OV-3, the more resistant cell lines, exhibited lower growth rates. Our findings indicate that the presence of p53 protein is a possible determinant for the cytotoxicity induced by irradiation in the investigated ovarian carcinoma cell lines. Bcl-2 expression does not seem to determine the response to irradiation in these cell lines. Additionally, an association between radioresponsiveness and the growth rate is suggested in PA-1, Caov-3, and SK-OV-3.