J.M. Lancaster

Identification of two distinct deleted regions on chromosome 13 in prostate cancer.

Aberrations of 13q occur frequently in prostate cancer and this chromosome contains two known tumor suppressor genes, BRCA2 and Rb1. This study analysed 13q LOH, DNA ploidy, BRCA2 mutation and pRb expression in prostate cancers. In total, 13q deletions were found in 18 of 36 tumors but did not correlate with histological grade, stage or DNA ploidy. Two smallest regions of overlapping deletions were defined: one flanked by D13S218 and D13S153; the other flanked by D13S31 and D13S137. BRCA2 was less frequently deleted whereas Rb1 did have a high frequency of deletion. None of the two genes was located in any of these two regions. Furthermore, BRCA2 mutation was not found in the five tumors where deletions had involved the BRCA2 locus. Neither did the Rb1 deletion correlate with absent pRb expression. In addition, tetraploidy was found in 14 out of 25 tumors analysed and correlated with aberrant pRb expression. Our results indicate that 13q deletion is an early non-random event. Tumor suppressor genes other than BRCA2 or Rb1 may be the target of 13q deletions. Aberrant pRb expression may not reflect the two-hit Rb1 inactivation but may be involved in the tetraploidization of prostate cancer cells.

Ovarian Adenocarcinomas in the Laying Hen and Women Share Similar Alterations in p53, ras, and HER-2/neu

We examined alterations in the p53 tumor suppressor gene and the ras and HER-2/neu oncogenes in chicken ovarian cancers to determine if these tumors have genetic alterations similar to those in human ovarian adenocarcinomas. Mutations in the p53 tumor suppressor gene and the H-ras and K-ras oncogenes were assessed by direct sequencing in 172 ovarian cancers obtained from 4-year-old birds enrolled at age 2 in two separate 2-year chemoprevention trials. Birds in trial B had approximately twice as many lifetime ovulations as those in trial A. Immunohistochemical staining for the HER-2/neu oncogene was done on a subset of avian ovarian and oviductal adenocarcinomas. Alterations in p53 were detected in 48% of chicken ovarian cancers. Incidence of p53 alterations varied according to the number of lifetime ovulations, ranging from 14% in trial A to 96% in trial B (P < 0.01). No mutations were seen in H-ras, and only 2 of 172 (1.2%) tumors had K-ras mutations. Significant HER-2/neu staining was noted in 10 of 19 ovarian adenocarcinomas but in only 1 of 17 oviductal adenocarcinomas. Similar to human ovarian cancers, p53 alterations are common in chicken ovarian adenocarcinomas and correlate with the number of lifetime ovulations. Ras mutations are rare, similar to high-grade human ovarian cancers. HER-2/neu overexpression is common and may represent a marker to exclude an oviductal origin in cancers involving both the ovary and oviduct.

In vitro analysis of ovarian cancer response to cisplatin, carboplatin, and paclitaxel identifies common pathways that are also associated with overall patient survival.

Background:Carboplatin and cisplatin, alone or in combination with paclitaxel, have similar efficacies against ovarian cancer (OVCA) yet exhibit different toxicity profiles. We characterised the common and unique cellular pathways that underlie OVCA response to these drugs and analyse whether they have a role in OVCA survival.Methods:Ovarian cancer cell lines (n=36) were treated with carboplatin, cisplatin, paclitaxel, or carboplatin–paclitaxel (CPTX). For each cell line, IC50 levels were quantified and pre-treatment gene expression analyses were performed. Genes demonstrating expression/IC50 correlations (measured by Pearson; P<0.01) were subjected to biological pathway analysis. An independent OVCA clinico-genomic data set (n=142) was evaluated for clinical features associated with represented pathways.Results:Cell line sensitivity to carboplatin, cisplatin, paclitaxel, and CPTX was associated with the expression of 77, 68, 64, and 25 biological pathways (P<0.01), respectively. We found three common pathways when drug combinations were compared. Expression of one pathway (‘Transcription/CREB pathway’) was associated with OVCA overall survival.Conclusion:The identification of the Transcription/CREB pathway (associated with OVCA cell line platinum sensitivity and overall survival) could improve patient stratification for treatment with current therapies and the rational selection of future OVCA therapy agents targeted to these pathways.

Evidence of a Chemopreventive Effect of Progestin Unrelated to Ovulation on Reproductive Tract Cancers in the Egg-laying Hen

Epidemiologic, laboratory, and animal evidence suggests that progestins and vitamin D may be potent ovarian cancer preventives. Our objectives were to evaluate progestins as reproductive tract cancer chemopreventives in the chicken, determine whether restricted ovulation affected the incidence of reproductive tract tumors, and assess whether vitamin D would confer cancer protection either alone or in addition to progestin. A total of 2,400 two-year-old Single Comb White Leghorns were randomized into six groups (400 each) with hormonal and dietary manipulation for 2 years as follows: (i) no intervention, regular feed/caloric intake, (ii) control, (iii) vitamin D, (iv) the progestin levonorgestrel, (v) vitamin D plus levonorgestrel, and (vi) the progestin Provera (medroxyprogesterone acetate). Groups 2 to 6 were caloric restricted to inhibit ovulation. Our results indicated that caloric restriction decreased egg production by more than 60%, and was associated with a greater than 70% decrease in reproductive tract cancers. Ovulatory events did not differ among the caloric-restricted groups (groups 2–6), except for the group receiving levonorgestrel, which had fewer ovulatory events than controls (P = 0.046). After correcting for egg production, birds receiving progestins had significantly fewer reproductive tract cancers [OR, 0.61; confidence interval (CI), 0.39–0.95; P = 0.03], with similar proportionate reductions in tumors arising in either the ovary or oviduct. Vitamin D did not significantly affect cancer incidence overall, or add to the cancer preventive effect of progestins. This study suggests a protective effect of progestins against ovarian and oviductal cancers. These data support the concept that progestins provide a chemopreventive effect unrelated to ovulation. Cancer Prev Res; 6(12); 1283–92. ©2013 AACR.

Gene expression determinants of ovarian cancer platinum-response in older women

22059 Background: Epithelial ovarian cancer (EOC) is the most lethal gynecologic malignancy, and more than half of new ovarian cancer cases arise in women over age 65. Although older women with EOC have poorer overall prognosis compared to younger women, the exact molecular basis to this difference remains unclear. The goal of this study is to improve our understanding of the molecular underpinnings of advanced stage EOC in older women and identify genes associated with chemo-response in older women such that therapy may be tailored to individual patients. Methods: We performed Affymetrix microarray gene expression analysis on 122 primary advanced stage epithelial ovarian cancers resected from 73 younger ( 65 years) women. For each age group, gene expression data was compared using Significance Analysis of Microarrays (SAM), between patients who demonstrated a complete-response (>65 years, n=38; 65 years, n=11; <65 years, n=25) to primary...

Expression Analysis of Genes Involved in Ovarian Cancer Metastasis.

5038 Background: Epithelial ovarian cancer is the most lethal gynecologic malignancy. Patients with early stage ovarian cancer have an excellent prognosis, in contrast to patients with advanced sta...

Gene expression profiles that predict response to platinum and identify patterns of pathway deregulation in advanced ovarian cancer

5031 Background: Platinum drugs are the most active agents in epithelial ovarian cancer, however 30% of patients with advanced disease have an incomplete response. Current treatment strategies result in many patients receiving multiple cycles of platinum-based chemotherapy without complete response. We have developed gene expression profiles that predict response to platinum therapy, with the aim of individualizing therapy. In parallel, we identified patterns of oncogenic pathway deregulation within the non-responding patient group that provides a rational basis for directing targeted therapeutics. Methods: Affymetrix GeneChips were used to measure gene expression in 120 stage III/IV serous ovarian cancers from patients who underwent primary surgical cytoreduction followed by platinum therapy. Expression data was compared between cancers that demonstrated a complete and incomplete response to platinum therapy. Predictive models were developed to distinguish patients likely to respond to therapy. In additi...