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Objective Recurrence and subsequent acquired chemoresistance to platinum-based treatments constitute major hurdles to ovarian carcinoma therapy. Our objective was to examine the involvement of Bcl-x L anti-apoptotic protein in resistance to cisplatin. Methods We described the effect of cisplatin on cell cycle and apoptosis induction in sensitive (IGROV1 and OAW42) and resistant (IGROV1-R10 and SKOV3) ovarian carcinoma cell lines. We correlated it with Bcl-x L mRNA and protein expression after exposure to cisplatin. We then used bcl - x S gene transfer to impede Bcl-x L activity. Results Our study showed that Bcl-x L basal expression was high in both sensitive and resistant cell lines, as well as in all the studied ovarian tumor samples. Thus, Bcl-x L basal expression could not allow to predict sensitivity. Wondering whether variation of Bcl-x L level in response to cisplatin could be a better determinant of sensitivity, we investigated the expression of this protein in the cell lines after treatment. Cisplatin-induced down-regulation of Bcl-x L was strictly associated with apoptosis and absence of recurrence in vitro. Conversely, the maintenance of Bcl-x L expression in response to cisplatin appeared as a sine qua non condition to escape to treatment. To try to sensitize SKOV3 cells by impeding anti-apoptotic activity of Bcl-x L , we transfected bcl-x S gene in these cells. Bcl-x S exogenous expression was only slightly cytotoxic on its own, but highly sensitized SKOV3 resistant cells to cisplatin-induced apoptosis, and delayed recurrence. Conclusion This work thus provides one more argument to put Bcl-x L forward as a pertinent target of inhibition to overcome chemoresistance of epithelial ovarian carcinoma.

International audience; The seriousness of ovarian cancer, which is related to the observed link between recurrency and cell cycle control defect, prompted us to explore the effect of ectopic expression of the cdk inhibitor p21cip1/waf1 on ovarian carcinoma chemosensitivity. The transfection of p21cip1/waf1 cDNA into SKOV3 and OVCAR3 cells led to reduction of tumor cell growth, enhanced susceptibility to cisplatin-induced apoptosis, and abolition of recurrency after cisplatin exposure. p21cip1/waf1 gene transfer allowed a marked reduction of the cisplatin concentration needed to erradicate the tumor cell population. These results suggest exploring the possible use of p21cip1/waf1 as an adjunctive to conventional chemotherapy.

The clinical relevance of DNA image cytometry (ICM) and flow cytometry (FCM) remains under investigation in breast carcinoma. The objective of the current work was to study the prognostic value of DNA ICM and FCM in a series of patients randomized in a control trial. A multivariate analysis has been performed including other factors still under investigation such as Ki-67 index, mitotic count, microvessel density, and P53 and Bcl-2 expression.Two hundred and eighty-one patients were randomized in the European Organization for Research and Treatment of Cancer 10854 trial comparing surgery followed by one course of perioperative chemotherapy versus surgery alone. Tumor parameters studied were pT, multicentricity, tumor grading according to modified Scarff-Bloom-Richardson, estrogen receptors, mitotic count per 1.7 mm(2), MIB-1, and BCL-2 scores, microvessel density, and p53 expression. ICM DNA parameters studied from paraffin embedded specimens, were DNA ploidy, proliferative index, 2c deviation index, malignancy grade, and Auer-Baldetorp typing. FCM DNA parameters analyzed on the same samples were ploidy and S-phase fraction statistics. The influence of tumor parameters, and DNA parameters on overall survival (OS), disease free survival (DFS), and metastasis-free survival (MFS) was evaluated using the Cox model. Median follow-up was 82 months.For OS, the prognostic parameters retained were pathologic tumor size (pT) and mitotic index (MI). Overall survival was 94% and 68% for tumors pT1/MI less than 10 and pT2-3 MI greater than or equal to 10, respectively. For DFS, age, multicentricity, and grading according to modified Scarff and Bloom were predicting factors with the same relative risk. Disease free survival was 96%, 78% and 68% respectively, when 1, 2, or 3 of those factors were present. For MFS, the only retained predicting factor was MI. MFS was 97% and 73% when MI was less than 10 and MI was greater than or equal to 10, respectively.Evaluation of proliferative compartment was the most important predicting factor for OS and MFS in the current series of premenopausal lymph node negative patients with breast invasive carcinoma. When working on paraffin embedded tissue, the best way of assessing it was MI count. ICM DNA analysis results were not selected in multivariate analysis. DNA analysis by FCM should be considered as an unsuitable technique when working on paraffin embedded tissue.

From 1990-1996, 1,485 previously untreated invasive breast carcinomas were sampled by a pathologist for flow cytometric DNA analysis. The aim of the present work was to study the variations of flow cytometric DNA ploidy and S-phase evaluation according to the conditions of DNA histogram interpretation. Results obtained with the American Consensus guidelines of 1993 and the François Baclesse Department of Pathology's own guidelines are presented. According to the percentage of events taken into account to identify a DNA aneuploid peak, the proportion of DNA diploid cases can change from 35-39%. For S-phase evaluation, although the two guidelines were quite different, the results of S-phase cutoff were identical. Whichever guidelines were used, there was a strong relationship between DNA ploidy and/or S-phase and classical clinicopathological factors (T, N, histological type, grade, receptor status, or lymphatic invasion), with the exception of age, whose correlation was discrepant with S phase according to the set of guidelines. Whichever guidelines were used, ploidy and S phase correlated strongly with survival (overall, metastasis-free, or recurrence-free). Hence we recommend the use of the American consensus guidelines, despite minor imperfections, because they are now well-known, allow a high yield in the ratio of assessable S phases, and permit standardization in the technical processing and reporting of S phases, thanks to the use of terciles.

Image cytometry has proved to provide a good alternative to flow cytometry for DNA ploidy measurement of archival tumors. However, when interactively done this technique is unable to give statistically valuable results within an acceptable time for clinical oncology.An image cytometer was developed for fully automatic DNA ploidy quantitation, focusing efforts on speed and accuracy. Software functionalities include systematic acquisition of fields on a microscopic slide, detection, localization and sorting of nuclei, computation of the DNA content together with post-processing tools, for a deeper analysis of the DNA ploidy diagram.DNA ploidy analysis of archival breast carcinoma samples illustrates the accuracy of DNA ploidy measurements and the sensitivity in the detection of DNA ploidy abnormalities as a result of cell sorting.Fully automatic image cytometry is able to combine qualities of flow cytometry (automatic analysis of a statistically significant collection of cell nuclei) with additional advantages: sorting of unwanted events (debris, stromal and inflammatory cell nuclei) and facilities for an a posteriori control of the quality of cell selection. This method is well suited to DNA ploidy analysis of archival cancer samples.

Chemoresistance is a major concern in cancer erradication; it involves various mechanisms, including defects in the apoptosis program induced by anticancer drugs. In order to further explore the mechanisms underlying the development of chemoresistance in ovarian carcinoma after cisplatin treatment, we established an in vitro model, mimicking a clinical protocol of administration of cisplatin. Therefore, IGROV1 ovarian carcinoma cells were exposed for 2 hr to the drug and allowed to recover for several weeks; this way of exposure was reiterated with escalating doses. We followed changes in cytotoxicity of the drug, cell cycle kinetics and long-term survival of cells after cisplatin treatment, and found that resistance to cisplatin was not associated with altered apoptosis pathway, since both cisplatin sensitive and resistant cells underwent apoptosis in a similar way. Acquisition of resistance to cisplatin was associated with the ability of the treated cells to progress through the cell cycle beyond the G1/S checkpoint; although most cells died by apoptosis, a few surviving cells proliferated and recolonized the cultures. Compared to sensitive cells, the chemoresistant variants were able to override the G1/S checkpoint whatever the dose, and the recurrent cells recolonized the cultures much faster. Analysis of alterations in gene expression suggests that the defect in cell cycle regulation could take place at the level of the cdk inhibitor p21(CIP1/WAF1).

The possibility to perform flow cytometry was examined in a series of 167 patients with primary untreated head and neck carcinoma referred to our Institution from February 1989 to January 1992. In all cases, flow cytometry was carried out on frozen tumour samples. The Cox model was used including age, tumour size, nodal status on clinical assessment, topography, treatment, malignancy grade, S phase fraction and ploidy as independent variables and overall survival as dependent variable. In this study, ploidy could be assessed in only 73% of cases and S phase fraction and G2M in 65% of the population studied. No correlation could be evidenced between ploidy or SPF with other clinical, pathologic characteristics or clinical outcome. We conclude that flow cytometry should remain a research tool until the method has proved to be relevant in clinical routine, and until the yield of the technique can be improved.

An automatic machine, dedicated to solid tumor DNA ploidy quantitation has been built in order to provide pathologists with a tool usable in clinical practice. Main efforts were focused on an automation of each step of the analysis and on an elimination of any subjective choice, while preserving the quality of measurement. As the software is independent of the machine architecture, it offers performances which increase in parallel with the rapid evolution of the computers. An illustration of the various functionalities of the automaton is proposed through the study of deparaffined breast cancer samples.