Results of TRIO-15, a multicenter, open-label, phase II study of the efficacy and safety of ganitumab in patients with recurrent platinum-sensitive ovarian cancer.

BACKGROUND: IGF signaling has been implicated in the pathogenesis and progression of ovarian carcinoma (OC). Single agent activity and safety of ganitumab (AMG 479), a fully human monoclonal antibody against IGF1R that blocks binding of IGF1 and IGF2, were evaluated in patients with platinum-sensitive recurrent OC. METHODS: Patients with CA125 progression (GCIG criteria) or measurable disease per RECIST following primary platinum-based therapy received 18 mg/kg of ganitumab q3w. The primary endpoint was objective response rate (ORR) assessed per RECIST 1.1 by an independent radiology review committee (IRC) and/or GCIG CA125 criteria. Secondary endpoints included clinical benefit rate (CBR), progression free survival (PFS) and overall survival (OS). RESULTS: 61 pts. were accrued. Objective responses were seen in 5/61 patients (ORR 8.2%, 95% CI, 3.1-18.8) with 1 partial response (PR) by RECIST and 2 complete responses (CR) as well as 2 PR by CA125 criteria. CBR was 80.3% (95% CI, 67.8-89.0%). The median PFS according to RECIST by IRC was 2.1 months (95% CI, 2.0-3.1). The median PFS per RECIST IRC and/or CA125 was 2.0 months (95% CI, 1.8-2.2). The median OS was 21 months (95% CI, 19.5-NA). The most common overall adverse events were fatigue (36.1%) and hypertension (34.4%). Grade 1/2 hyperglycemia occurred in 30.4% of patients. Hypertension (11.5%) and hypersensitivity (8.2%) were the most frequent grade 3 adverse events. CONCLUSIONS: IGF1R inhibition with ganitumab was well-tolerated, however, our results do not support further study of ganitumab as a single agent in unselected OC patients.

Results of TRIO-14, a phase II, multicenter, randomized, placebo-controlled trial of carboplatin-paclitaxel versus carboplatin-paclitaxel-ganitumab in newly diagnosed epithelial ovarian cancer.

PURPOSE: Insulin-like growth factor (IGF) signaling is implicated in pathogenesis and chemotherapy resistance of epithelial ovarian cancer (EOC). We explored efficacy and safety of adding ganitumab, a monoclonal antibody targeting IGF-1R, to carboplatin/paclitaxel (CP) chemotherapy in patients with primary EOC. DESIGN: Patients were randomly assigned to receive CP/ganitumab (18 mg/kg q3w) or CP/placebo for 6 cycles followed by 6 cycles of single agent ganitumab/placebo maintenance therapy as front-line therapy. Primary endpoint was progression free survival. Secondary endpoints were time to progression and overall survival. Pretreatment samples were prospectively collected for retrospective biomarker analyses. RESULTS: 170 patients enrolled. 165 patients assessable for toxicity. Median PFS was 15.7 months with CP/ganitumab and 16.7 months with CP/placebo (HR 1.23; 95% CI 0.82-1.83, P = 0.313). All grade neutropenia (84.1% vs 71.4%), thrombocytopenia (75.3% vs 57.1%) and hyperglycemia (15.9% vs 2.6%) were more common in the ganitumab group compared to the placebo group. Ganitumab/placebo related serious adverse events were reported in 26.1% of the patients with ganitumab and in 6.5% with placebo. Non-progression related fatal events were more common with ganitumab (5 versus 2 patients). The ganitumab group experienced more dose delays which resulted in lower relative dose intensity of chemotherapy in the experimental group. In an exploratory model IGFBP2 expression was predictive of ganitumab response (treatment interaction; PFS, P = 0.03; OS, P = 0.01). CONCLUSION: Addition of ganitumab to CP chemotherapy in primary EOC did not improve PFS. Our results do not support further study of ganitumab in unselected EOC patients.

Antitumor activity and safety of pembrolizumab in patients with advanced recurrent ovarian cancer: results from the phase II KEYNOTE-100 study.

BACKGROUND: Advanced recurrent ovarian cancer (ROC) is the leading cause of gynecologic cancer-related death in developed countries and new treatments are needed. Previous studies of immune checkpoint blockade showed low objective response rates (ORR) in ROC with no identified predictive biomarker. PATIENTS AND METHODS: This phase II study of pembrolizumab (NCT02674061) examined two patient cohorts with ROC: cohort A received one to three prior lines of treatment with a platinum-free interval (PFI) or treatment-free interval (TFI) between 3 and 12 months and cohort B received four to six prior lines with a PFI/TFI of ≥3 months. Pembrolizumab 200 mg was administered intravenously every 3 weeks until cancer progression, toxicity, or completion of 2 years. Primary end points were ORR by Response Evaluation Criteria in Solid Tumors version 1.1 per blinded independent central review by cohort and by PD-L1 expression measured as combined positive score (CPS). Secondary end points included duration of response (DOR), disease control rate (DCR), progression-free survival (PFS), overall survival (OS), and safety. RESULTS: Cohort A enrolled 285 patients; the first 100 served as the training set for PD-L1 biomarker analysis. Cohort B enrolled 91 patients. ORR was 7.4% for cohort A and 9.9% for cohort B. Median DOR was 8.2 months for cohort A and not reached for cohort B. DCR was 37.2% and 37.4%, respectively, in cohorts A and B. Based on the training set analysis, CPS 1 and 10 were selected for evaluation in the confirmation set. In the confirmation set, ORR was 4.1% for CPS <1, 5.7% CPS ≥1, and 10.0% for CPS ≥10. PFS was 2.1 months for both cohorts. Median OS was not reached for cohort A and was 17.6 months for cohort B. Toxicities were consistent with other single-agent pembrolizumab trials. CONCLUSIONS: Single-agent pembrolizumab showed modest activity in patients with ROC. Higher PD-L1 expression was correlated with higher response. CLINICAL TRIAL NUMBER: Clinicaltrials.gov, NCT02674061.

OV21/PETROC: a randomized Gynecologic Cancer Intergroup phase II study of intraperitoneal versus intravenous chemotherapy following neoadjuvant chemotherapy and optimal debulking surgery in epithelial ovarian cancer.

Background: The purpose of this multistage, adaptively, designed randomized phase II study was to evaluate the role of intraperitoneal (i.p.) chemotherapy following neoadjuvant chemotherapy (NACT) and optimal debulking surgery in women with epithelial ovarian cancer (EOC). Patients and methods: We carried out a multicenter, two-stage, phase II trial. Eligible patients with stage IIB-IVA EOC treated with platinum-based intravenous (i.v.) NACT followed by optimal (<1 cm) debulking surgery were randomized to one of the three treatment arms: (i) i.v. carboplatin/paclitaxel, (ii) i.p. cisplatin plus i.v./i.p. paclitaxel, or (iii) i.p. carboplatin plus i.v./i.p. paclitaxel. The primary end point was 9-month progressive disease rate (PD9). Secondary end points included progression-free survival (PFS), overall survival (OS), toxicity, and quality of life (QOL). Results: Between 2009 and 2015, 275 patients were randomized; i.p. cisplatin containing arm did not progress beyond the first stage of the study after failing to meet the pre-set superiority rule. The final analysis compared i.v. carboplatin/paclitaxel (n = 101) with i.p. carboplatin, i.v./i.p. paclitaxel (n = 102). The intention to treat PD9 was lower in the i.p. carboplatin arm compared with the i.v. carboplatin arm: 24.5% (95% CI 16.2% to 32.9%) versus 38.6% (95% CI 29.1% to 48.1%) P = 0.065. The study was underpowered to detect differences in PFS: HR PFS 0.82 (95% CI 0.57-1.17); P = 0.27 and OS HR 0.80 (95% CI 0.47-1.35) P = 0.40. The i.p. carboplatin-based regimen was well tolerated with no reduction in QOL or increase in toxicity compared with i.v. administration alone. Conclusion: In women with stage IIIC or IVA EOC treated with NACT and optimal debulking surgery, i.p. carboplatin-based chemotherapy is well tolerated and associated with an improved PD9 compared with i.v. carboplatin-based chemotherapy. Clinical trial number: clinicaltrials.gov, NCT01622543.

Sentinel nodes in vulvar cancer: Long-term follow-up of the GROningen INternational Study on Sentinel nodes in Vulvar cancer (GROINSS-V) I.

OBJECTIVE: In 2008 GROINSS-V-I, the largest validation trial on the sentinel node (SN) procedure in vulvar cancer, showed that application of the SN-procedure in patients with early-stage vulvar cancer is safe. The current study aimed to evaluate long-term follow-up of these patients regarding recurrences and survival. METHODS: From 2000 until 2006 GROINSS-V-I included 377 patients with unifocal squamous cell carcinoma of the vulva (T1, <4 cm), who underwent the SN-procedure. Only in case of SN metastases an inguinofemoral lymphadenectomy was performed. For the present study follow-up was completed until March 2015. RESULTS: Themedian follow-up was 105 months (range 0­179). The overall local recurrence ratewas 27.2% at 5 years and 39.5% at 10 years after primary treatment, while for SN-negative patients 24.6% and 36.4%, and for SN-positive patients 33.2% and 46.4% respectively (p = 0.03). In 39/253 SN-negative patients (15.4%) an inguinofemoral lymphadenectomy was performed, because of a local recurrence. Isolated groin recurrence rate was 2.5% for SN-negative patients and 8.0% for SN-positive patients at 5 years. Disease-specific 10-year survival was 91% for SN-negative patients compared to 65% for SN-positive patients (p b .0001). For all patients, 10-year disease-specific survival decreased from 90% for patients without to 69% for patients with a local recurrence (p b .0001).

Transfer of chromosome 3 fragments suppresses tumorigenicity of an ovarian cancer cell line monoallelic for chromosome 3p.

Multiple chromosome 3p tumor suppressor genes (TSG) have been proposed in the pathogenesis of ovarian cancer based on complex patterns of 3p loss. To attain functional evidence in support of TSGs and identify candidate regions, we applied a chromosome transfer method involving cell fusions of the tumorigenic OV90 human ovarian cancer cell line, monoallelic for 3p and an irradiated mouse cell line containing a human chromosome 3 in order to derive OV90 hybrids containing normal 3p fragments. The resulting hybrids showed complete or incomplete suppression of tumorigenicity in nude mouse xenograft assays, and varied in their ability to form colonies in soft agarose and three-dimensional spheroids in a manner consistent with alteration of their in vivo tumorigenic phenotypes. Expression microarray analysis identified a set of common differentially expressed genes, such as SPARC, DAB2 and VEGF, some of which have been shown implicated in ovarian cancer. Genotyping assays revealed that they harbored normal 3p fragments, some of which overlapped candidate TSG regions (3p25-p26, 3p24 and 3p14-pcen) identified previously in loss of heterozygosity analyses of ovarian cancers. However, only the 3p12-pcen region was acquired in common by all hybrids where expression microarray analysis identified differentially expressed genes. The correlation of 3p12-pcen transfer and tumor suppression with a concerted re-programming of the cellular transcriptome suggest that the putative TSG may have affected key underlying events in ovarian cancer.

Construction of a chromosome 17 transcriptome in serous ovarian cancer identifies differentially expressed genes.

Cytogenetic, molecular genetic, and functional analyses have implicated chromosome 17 genes in epithelial ovarian cancer (EOC). To further characterize the contribution of chromosome 17 genes in EOC, the Affymetrix U133A GeneChip was used to perform transcriptome analyses of 15 primary cultures of normal ovarian surface epithelial (NOSE) cells and 17 malignant ovarian tumor (TOV) samples of the serous histopathologic subtype. A two-way comparative analysis of 776 known genes and expressed sequences identified 253 genes that exhibited at least a threefold difference in expression in at least one TOV sample compared to the mean of NOSE samples. Within this data set, 99 of the 253 (39.1%) genes exhibited similar patterns of expression across all tested samples, suggesting a high degree of concordance in the chromosome 17 transcriptome. This observation was supported by hierarchical clustering analysis that segregated the TOV and NOSE samples into two separate groups. There were 77 genes that were differentially expressed in at least 50% of the TOV samples. Five genes (AdoRA(2B)at 17p12, CCL2 at 17q12, ACLY at 17q21.2, WIPI1 at 17q24.2, and SLC16A3 at 17q25.3) were significantly (P < 5.13E-11) differentially expressed at least threefold in all serous TOV samples, and all five genes were underexpressed in these TOV samples as compared to the NOSE samples. Interestingly, several of these differentially expressed genes have been previously associated with response to hypoxia.

The contribution of germline rearrangements to the spectrum of BRCA2 mutations.

BACKGROUND: Few germline BRCA2 rearrangements have been described compared with the large number of germline rearrangements reported in the BRCA1 gene. However, some BRCA2 rearrangements have been reported in families that included at least one case of male breast cancer. OBJECTIVE: To estimate the contribution of large genomic rearrangements to the spectrum of BRCA2 defects. METHODS: Quantitative multiplex PCR of short fluorescent fragments (QMPSF) was used to screen the BRCA2 gene for germline rearrangements in highly selected families. QMPSF was previously used to detect heterozygous deletions/duplications in many genes including BRCA1 and BRCA2. RESULTS: We selected a subgroup of 194 high risk families with four or more breast cancers with an average age at diagnosis of < or = 50 years, who were recruited through 14 genetic counselling centres in France and one centre in Switzerland. BRCA2 mutations were detected in 18.6% (36 index cases) and BRCA1 mutations in 12.4% (24 index cases) of these families. Of the 134 BRCA1/2 negative index cases in this subgroup, 120 were screened for large rearrangements of BRCA2 using QMPSF. Novel and distinct BRCA2 deletions were detected in three families and their boundaries were determined. We found that genomic rearrangements represent 7.7% (95% confidence interval 0% to 16%) of the BRCA2 mutation spectrum. CONCLUSION: The molecular diagnosis of breast cancer predisposition should include screening for BRCA2 rearrangements, at least in families with a high probability of BRCA2 defects.

Immunohistochemical localization of P-glycoprotein in adult human ovary and female genital tract of patients with benign gynecological conditions.

The multidrug-resistance gene, MDR1, encodes a plasma membrane glycoprotein termed P-glycoprotein, which mediates active cellular efflux of certain cytotoxic agents. Two mouse monoclonal antibodies (MAb), C219 and JSB-1, were used to identify P-glycoprotein in frozen tissue from the female genital tract of 14 women with benign gynecological conditions; multiple samples from several sites in the genital tract were available from seven patients. P-glycoprotein was detected in the ovarian surface epithelium in four of 14 cases, in the Fallopian tube in three of five cases, in occasional epithelial cells of the endometrial glands in two of five cases, in some endocervical glandular epithelium in three of five cases, in ectocervical squamous epithelium in one of the two cases, and in luteinized cells of the eight cases in which a corpus luteum was present in the specimen. Positive staining with these two MAb was also observed in some endothelial cells in the cortex of the ovary and in the stromal tissue of the myometrium, endometrium, and endocervix. These studies suggest that, if epithelial ovarian cancers are derived from the surface epithelial cells of the ovary, a small proportion of the cancers might be expected to retain the phenotype found in non-cancerous cells and to express P-glycoprotein.

Chemosensitivity and radiosensitivity profiles of four new human epithelial ovarian cancer cell lines exhibiting genetic alterations in BRCA2, TGFbeta-RII, KRAS2, TP53 and/or CDNK2A.

To address the cellular basis for the response to ovarian cancer treatment, we characterized the chemosensitivity and radiosensitivity of four human epithelial ovarian cancer cell lines that harbor different genetic alterations. The TOV-21G, TOV-81D, OV-90, and TOV-112D cell lines were derived from ovarian tumors (TOV) or ascites (OV) from chemotherapy- and radiotherapy-naive patients and were characterized by their mutation spectrum of BRCA2, TGFbeta-RII, KRAS2, TP53, and CDKN2A. Cells were monitored for survival following exposure at various concentrations to different cytotoxic agents including cisplatin, camptothecin or paclitaxel or to different doses of gamma-irradiation. At the lowest doses, the TGFbeta-RII-mutated and KRAS2-mutated cell line, TOV-21G, and the BRCA2-mutated cell line, TOV-81D, demonstrated a significantly higher sensitivity to cisplatin and gamma-irradiation than the TP53-mutated cell lines, TOV-112D and OV-90. At higher doses, differences between the TP53-mutated lines were observed with TOV-112D being less sensitive to cisplatin than OV-90 that also harbors a CDNK2A mutation. All cell lines were similarly sensitive to high doses of gamma-irradiation. In contrast, sensitivity to camptothecin or paclitaxel was not significantly different between all cell lines, irrespective of the mutation status of BRCA1, BRCA2, TGFbeta-RII, KRAS2, TP53, and CDKN2A. The observed responses to treatment are consistent with the current knowledge concerning BRCA2, TGFbeta-RII, KRAS2, TP53, and/or CDKN2A aberrant function.

[Early detection of ovarian cancer: tomorrow? A review]. / Vers un dépistage possible du cancer de l'ovaire?

Ovarian cancer is the most lethal of the gynaecological malignancies because this «silent killer¼ is almost always diagnosed at an advanced stage. Precursor lesions have at least been discovered. This review will describe in details specific features of tubal and ovarian preinvasive lesions and the old and novel techniques that could be used for early detection of ovarian cancer.

A Phase II study of trabectedin single agent in patients with recurrent ovarian cancer previously treated with platinum-based regimens.

The objective of this study was to determine the objective response rate in patients with platinum-sensitive and platinum-resistant recurrent ovarian cancer to treatment with trabectedin (Yondelis) administered as a 3-h infusion weekly for 3 weeks of a 4-week cycle. We carried out a multicentre Phase II trial of trabectedin in patients with advanced recurrent ovarian cancer. Trabectedin (0.58 mg m(-2)) was administered via a central line, after premedication with dexamethasone, to 147 patients as a 3-h infusion weekly for 3 weeks followed by 1-week rest. Major eligibility criteria included measurable relapsed advanced ovarian cancer and not more than two prior platinum-containing regimens. Patients were stratified according to the treatment-free interval (TFI) between having either platinum-sensitive (>/=6 months TFI) or platinum-resistant disease (<6 months TFI)/platinum-refractory disease (progression during first line therapy). In the platinum-sensitive cohort, 62 evaluable patients with measurable disease had an overall response rate (ORR) of 29.0% (95% CI: 18.2-41.9%) and median progression-free survival (PFS) was 5.1 months (95% CI: 2.8-6.2). Four patients with measurable disease per Response Evaluation Criteria in Solid Tumours (RECIST) criteria had no follow-up scans at the end of treatment. In the platinum-resistant/refractory cohort, 79 patients were evaluable with an ORR of 6.3% (95% CI: 2.1-14.2%). Median PFS was 2.0 months (95% CI: 1.7-3.5 months). Two patients with measurable disease per RECIST criteria had no follow-up scans at the end of treatment. The most frequent (>/=2% of patients) drug-related treatment-emergent grade 3/4 adverse events were reversible liver alanine transferase elevation (10%), neutropaenia (8%), nausea, vomiting, and fatigue (5% each). Trabectedin is an active treatment, with documented responses in patients with platinum sensitive advanced relapsed ovarian cancer, and has a manageable toxicity profile.

Gene expression profiling of primary cultures of ovarian epithelial cells identifies novel molecular classifiers of ovarian cancer.

In order to elucidate the biological variance between normal ovarian surface epithelial (NOSE) and epithelial ovarian cancer (EOC) cells, and to build a molecular classifier to discover new markers distinguishing these cells, we analysed gene expression patterns of 65 primary cultures of these tissues by oligonucleotide microarray. Unsupervised clustering highlights three subgroups of tumours: low malignant potential tumours, invasive solid tumours and tumour cells derived from ascites. We selected 18 genes with expression profiles that enable the distinction of NOSE from these three groups of EOC with 92% accuracy. Validation using an independent published data set derived from tissues or primary cultures confirmed a high accuracy (87-96%). The distinctive expression pattern of a subset of genes was validated by quantitative reverse transcription-PCR. An ovarian-specific tissue array representing tissues from NOSE and EOC samples of various subtypes and grades was used to further assess the protein expression patterns of two differentially expressed genes (Msln and BMP-2) by immunohistochemistry. This study highlights the relevance of using primary cultures of epithelial ovarian cells as a model system for gene profiling studies and demonstrates that the statistical analysis of gene expression profiling is a useful approach for selecting novel molecular tumour markers.

Phase II multicenter open-label study of carboplatin and pegylated liposomal doxorubicin in uterine and cervical malignancies.

The results of a multicenter phase II study investigating carboplatin and pegylated liposomal doxorubicin (PLD) in patients with recurrent/metastatic uterine and cervical malignancies (UCM) are presented here. Fifty-three subjects with measurable, untreated, advanced UCM were enrolled. Fifty-one were evaluable for response. Prior combined-modality treatment was permitted if a component of primary therapy. Patients received carboplatin AUC = 5 with PLD 35 mg/m(2) intravenously once every 4 weeks. Overall response rate was 33% (35% stable disease). Overall survival (OS) at six months was 86% (95% CI 76%-96%). Six-month progression-free survival (PFS) was 43% (95% CI 30%-57%). Median PFS was 22.9 weeks (range 16.0-35.3) and median OS was 49.1 weeks (range 41.4-75.1). The most frequent grade 3-4 nonhematological adverse events were: abdominal pain (n = 7), fatigue (4), vomiting (4), nausea (3), and shortness of breath (3). There was 1 report of grade 3 hand-foot syndrome and none of grade 4. Twelve patients had first infusion reactions with only 1 discontinuing treatment. Grade 3-4 neutropenia occurred in 26/230 cycles (11.3%). There were no treatment-related deaths. The combination of carboplatin and PLD is well tolerated with sufficient activity to justify additional evaluation in clinical trials and might be suited to the addition of a taxane.

Discordance in p53 mutations when comparing ascites and solid tumors from patients with serous ovarian cancer.

We performed a mutational analysis of the p53 gene in matched samples of solid tumors and ascites from patients with ovarian cancer using the single-strand conformation polymorphism technique on exons 5-9 of the p53 gene on fresh and cultured material. We observed a discordance in the pattern of p53 mutations between the ascites and their solid tumor counterpart. In two cases, cancer cells from ascites carried a p53 mutation and the corresponding solid tumor cells retained the wild-type allele, while the opposite pattern was observed in two other patients samples. These results suggest that ovarian tumor cells within the ascites may not simply represent cells shed from the ovarian solid tumor and bear directly on gene therapy strategies in ovarian cancer.

Expression of FHIT in primary cultures of human epithelial ovarian tumors and malignant ovarian ascites.

Abnormal FHIT gene expression has been reported in a variety of epithelial tumors shown to harbor deletions of chromosome 3p14, the chromosomal assignment of this gene. Recently, we described loss of heterozygosity of 3p in a subset of epithelial ovarian cancers. To investigate a potential role of the FHIT gene in ovarian cancer, we examined primary cell cultures derived from normal ovarian surface epithelium, ovarian tumors, and the cellular fraction of malignant ascites to determine the expression of FHIT by using reverse transcription-polymerase chain reaction. Included in this analysis were four spontaneously immortalized cell lines: three derived from malignant epithelial ovarian tumors (TOV21G, TOV112D, and TOV81D) and one from malignant ovarian ascites (OV90). OV90 was previously shown to harbor a deletion of the whole p arm of chromosome 3. The FHIT transcript was not detectable in two of 11 primary cultures derived from normal ovarian surface epithelium or in a primary culture derived from malignant ovarian ascites, whereas the remaining samples (34 malignant, eight borderline, and three benign specimens), exhibited identical expression patterns. In each case, this pattern was consistent with the co-expression of a normal FHIT transcript and a smaller transcript. DNA sequencing revealed that the abnormal-sized message lacked exons 4-7 (inclusive), which were deleted at their exact intron-exon splice sites. The aberrant-sized transcript was detectable by Northern blot analysis. There was no concordance between FHIT expression and loss of heterozygosity at the FHIT locus. Northern blot analysis also revealed that FHIT was differentially expressed, and the spontaneously immortalized cell lines TOV21G and TOV112D showed the highest level of expression. Because the same reverse transcription-polymerase chain reaction expression pattern was observed in both normal and tumor-derived primary cell cultures, these results argue against a significant role for FHIT in epithelial ovarian tumorigenesis.

Expression of P-glycoprotein in epithelial ovarian cancer: evaluation as a marker of multidrug resistance.

The multidrug-resistance gene, MDR1, encodes a plasma membrane glycoprotein termed P-glycoprotein that mediates active cellular efflux of certain chemotherapeutic agents. P-Glycoprotein expression was evaluated in 98 frozen tumor specimens from 57 patients with epithelial ovarian cancer by the indirect immunoperoxidase technique with monoclonal antibodies C219 and JSB-1 used for detection. Tumor specimens were further characterized antigenically with a panel of monoclonal antibodies representing a variety of epithelial cell antigens. Included were 57 specimens from 33 previously untreated patients; 11 specimens were also available from eight patients in this group after chemotherapy. An additional 30 specimens were studied from 24 other patients after chemotherapy. In only four of the 57 patients with ovarian cancer (7%) did one or more of the specimens express P-glycoprotein. Two of these patients had tumors that were considered clinically drug resistant. No increase in P-glycoprotein expression was noted after exposure to chemotherapy, including the eight individuals for whom specimens were available both before and after treatment. Although drug resistance is a major problem in treatment of ovarian cancer, resistance to the drugs most active against these tumors probably occurs through a mechanism other than expression of the MDR1 gene product.

Comparison of antigen expression on fresh and cultured ascites cells and on solid tumors of patients with epithelial ovarian cancer.

The antigenic phenotype of malignant cells from ascites of patients with epithelial ovarian cancers was examined and compared to that of their primary and metastatic sites. Cell-surface antigens on frozen sections of primary and metastatic tumors and frozen cell pellets from ascites were analyzed with a panel of murine monoclonal antibodies using the indirect immunoperoxidase method. In addition, ascites cells cultured with and without autologous cell-free ascitic fluid were evaluated by immunofluorescence. The pattern of antigen expression detected on fresh and cultured ascitic epithelial cells was shown to be identical to the expression in autologous solid tumor tissues. When placed in culture, malignant epithelial cells generally persisted for a minimum of one, but no more than five, passages. Addition of autologous ascitic fluid to cultures of ascites cells did not alter the phenotype of the epithelial tumor cell population and did not enhance the growth of these cells. From one culture of ascites cells a permanent malignant epithelial ovarian cancer cell line (designated SK-OV-8) was established. The demonstration that epithelial tumor cells found in ascites of patients with epithelial ovarian cancer have the identical antigenic phenotype as their solid tumor counterpart, at least for the panel of antigens studied, may be useful in planning imaging and therapeutic trials with monoclonal antibodies.