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2 protein expression as a potential marker of the BRCAness syndrome in ovarian cancer
Abstracts / Gynecologic Oncology 133 (2014) 2–207
gross resection (CR) as a function of DS, CS, the DS/CS interaction, and other possible confounders. Given the DS/CS interaction, the primary effect of DS on RD remained statistically significant (P b 0.01), while the main effect of CS was not (P = 0.23). This finding suggests that CS did not directly affect RD but instead had an indirect effect on RD through its moderation of the DS effect. Within high-DS patients, those with high CS were significantly more likely to obtain CR than those with low CS or moderate CS (P b 0.01 for both). Within the low-DS and moderate-DS patients, the probability of MR was not affected by CS (P = 0.68). Repeating this model in patients from institutions in which CR rates were N40% gave similar results, suggesting no evidence for institutional bias. The effects of DS and RD status on prognosis were both statistically significant (P b 0.01). Patients with CR had better prognoses than those with b1 cm RD (P b 0.01). After controlling for DS, RD, an interaction term for DS/CS, performance status, age, and cell type, CS did not have any effect on PFS or OS. Conclusions: Initial disease burden reflected in the DS is a principal determinant of RD, PFS, and OS following surgical cytoreduction. Data from the current study suggest that aggressive surgical cytoreduction provides by far the greatest benefit when CR is achieved. doi:10.1016/j.ygyno.2014.03.061
42 - Featured Poster BRCA1/2 protein expression as a potential marker of the BRCAness syndrome in ovarian cancer J.C. Mejia. Instituto Nacional de Cancerología, Mexico City, Mexico. Objectives: To determine whether the level of BRCA1/2 protein expression is one of the biologic characteristics of the BRCAness clinical syndrome, we analyzed the relationship between the clinical outcome of primary ovarian cancer patients and the expression of BRCA1/2 protein in tumor tissue. We also sought to assess the potential value of BRCA1/2 protein expression as a prognostic and/or predictive biologic parameter in sporadic ovarian cancer. Methods: This large retrospective cohort examined 126 patients with primary epithelial ovarian cancer (EOC). A tumor tissue fragment from each case, cryopreserved at the tumoral bank and containing high amount of tumor cells, was analyzed. Inclusion criteria were: primary ovarian cancer, FIGO stages I-IV, and primary cytoreductive surgery followed by chemotherapy with platinum or combination of taxane/platinum regimens. We used Western blot and quantitative real-time polymerase chain reaction to evaluate the abundance and the expression of BRCA1/2. Overall survival (OS) was calculated from date of surgery to date of death due to ovarian cancer (time in months) for patients with negative vs positive BRCA 1/2 protein expression, low vs high grade and stage via Kaplan– Meier log rank test. Odds ratio were conducted using multivariate logistic regression, applying the proportional odds model to assess evidence of no association between BRCA1 and other clinical parameters (age, grade, and stage) in survival analysis. Results: Patients with absent BRCA1 protein expression had a significantly improved OS and progression-free survival (Kaplan–Meier statistical analysis) following treatment compared with patients with positive BRCA1 protein expression. Analysis of the BRCA1/2 mRNA level did not demonstrate a significant link related to survival. We believe that this is related to the weak level of mRNA expression. Conclusions: There was a poor correlation between mRNA and protein expression levels of BRCA1 or BRCA2. There was no significant link between BRCA1/2 mRNA expression level and disease outcome. There was a significant correlation between BRCA1 loss of expression and an improved outcome for ovarian cancer. These results suggest that BRCA1 protein expression could be one of the biologic parameters associated with the BRCAness clinical syndrome.
17
doi:10.1016/j.ygyno.2014.03.062
43 - Featured Poster Identification of candidate circulating cisplatin resistance biomarkers from epithelial ovarian carcinoma cell secretomes P.N. Teng1, G. Wang1, B.L. Hood1, K.A. Conrads1, C.A. Hamilton2, G.L. Maxwell3, K.M. Darcy1, T.P. Conrads1. 1Gynecologic Cancer Center of Excellence, Annandale, VA, USA, 2Walter Reed National Military Medical Center, Bethesda, MD, USA, 3Inova Fairfax Hospital, Falls Church, VA, USA. Objectives: Most patients diagnosed with advanced epithelial ovarian carcinoma (EOC) relapse with resistant disease, and there are no clinically useful biomarkers to identify or monitor this resistance. This study sought to identify differential secreted proteins collected from human EOC cell lines of varying platinum sensitivity. Methods: Secreted proteins collected from conditioned medium from five ovarian cancer cell lines that varied in their sensitivity to cisplatin were digested with trypsin and analyzed by liquid chromatography– tandem mass spectrometry for peptide identification. Significantly altered proteins were validated in independent biologic replicates by immunoblotting. Survival analyses were performed using public gene expression data to interrogate candidate biomarkers that passed immunoblot verification to evaluate the clinical relevance. Results: Among the 1688 proteins identified, 16 were differentially abundant (P b 0.05) between platinum-resistant and -sensitive ovarian cancer cell lines. Approximately 60% of the identified secretome proteins were also found in the human plasma proteome and/or were annotated in the secreted protein database. A number of the significant differential secretome proteins were verified by immunoblot, including COL11A1, which was also found to be associated with worse progression-free survival (PFS) (n = 723, P = 0.0003) and overall survival (OS) (n = 1183, P = 7 × 10− 5), as assessed from publicly available transcript expression data from ovarian cancer tumor specimens (Fig. 1).
Fig. 1. Kaplan–Meier plots for PFS (A) and OS (B) in ovarian cancer patients with low (≤median) or high (N median) tumor expression of COL11A1 assessed from the average of two probes (median = 6.8722). There were 723 women included in the PFS and 1183 women included in the OS analysis.
gross resection (CR) as a function of DS, CS, the DS/CS interaction, and other possible confounders. Given the DS/CS interaction, the primary effect of DS on RD remained statistically significant (P b 0.01), while the main effect of CS was not (P = 0.23). This finding suggests that CS did not directly affect RD but instead had an indirect effect on RD through its moderation of the DS effect. Within high-DS patients, those with high CS were significantly more likely to obtain CR than those with low CS or moderate CS (P b 0.01 for both). Within the low-DS and moderate-DS patients, the probability of MR was not affected by CS (P = 0.68). Repeating this model in patients from institutions in which CR rates were N40% gave similar results, suggesting no evidence for institutional bias. The effects of DS and RD status on prognosis were both statistically significant (P b 0.01). Patients with CR had better prognoses than those with b1 cm RD (P b 0.01). After controlling for DS, RD, an interaction term for DS/CS, performance status, age, and cell type, CS did not have any effect on PFS or OS. Conclusions: Initial disease burden reflected in the DS is a principal determinant of RD, PFS, and OS following surgical cytoreduction. Data from the current study suggest that aggressive surgical cytoreduction provides by far the greatest benefit when CR is achieved. doi:10.1016/j.ygyno.2014.03.061
42 - Featured Poster BRCA1/2 protein expression as a potential marker of the BRCAness syndrome in ovarian cancer J.C. Mejia. Instituto Nacional de Cancerología, Mexico City, Mexico. Objectives: To determine whether the level of BRCA1/2 protein expression is one of the biologic characteristics of the BRCAness clinical syndrome, we analyzed the relationship between the clinical outcome of primary ovarian cancer patients and the expression of BRCA1/2 protein in tumor tissue. We also sought to assess the potential value of BRCA1/2 protein expression as a prognostic and/or predictive biologic parameter in sporadic ovarian cancer. Methods: This large retrospective cohort examined 126 patients with primary epithelial ovarian cancer (EOC). A tumor tissue fragment from each case, cryopreserved at the tumoral bank and containing high amount of tumor cells, was analyzed. Inclusion criteria were: primary ovarian cancer, FIGO stages I-IV, and primary cytoreductive surgery followed by chemotherapy with platinum or combination of taxane/platinum regimens. We used Western blot and quantitative real-time polymerase chain reaction to evaluate the abundance and the expression of BRCA1/2. Overall survival (OS) was calculated from date of surgery to date of death due to ovarian cancer (time in months) for patients with negative vs positive BRCA 1/2 protein expression, low vs high grade and stage via Kaplan– Meier log rank test. Odds ratio were conducted using multivariate logistic regression, applying the proportional odds model to assess evidence of no association between BRCA1 and other clinical parameters (age, grade, and stage) in survival analysis. Results: Patients with absent BRCA1 protein expression had a significantly improved OS and progression-free survival (Kaplan–Meier statistical analysis) following treatment compared with patients with positive BRCA1 protein expression. Analysis of the BRCA1/2 mRNA level did not demonstrate a significant link related to survival. We believe that this is related to the weak level of mRNA expression. Conclusions: There was a poor correlation between mRNA and protein expression levels of BRCA1 or BRCA2. There was no significant link between BRCA1/2 mRNA expression level and disease outcome. There was a significant correlation between BRCA1 loss of expression and an improved outcome for ovarian cancer. These results suggest that BRCA1 protein expression could be one of the biologic parameters associated with the BRCAness clinical syndrome.
17
doi:10.1016/j.ygyno.2014.03.062
43 - Featured Poster Identification of candidate circulating cisplatin resistance biomarkers from epithelial ovarian carcinoma cell secretomes P.N. Teng1, G. Wang1, B.L. Hood1, K.A. Conrads1, C.A. Hamilton2, G.L. Maxwell3, K.M. Darcy1, T.P. Conrads1. 1Gynecologic Cancer Center of Excellence, Annandale, VA, USA, 2Walter Reed National Military Medical Center, Bethesda, MD, USA, 3Inova Fairfax Hospital, Falls Church, VA, USA. Objectives: Most patients diagnosed with advanced epithelial ovarian carcinoma (EOC) relapse with resistant disease, and there are no clinically useful biomarkers to identify or monitor this resistance. This study sought to identify differential secreted proteins collected from human EOC cell lines of varying platinum sensitivity. Methods: Secreted proteins collected from conditioned medium from five ovarian cancer cell lines that varied in their sensitivity to cisplatin were digested with trypsin and analyzed by liquid chromatography– tandem mass spectrometry for peptide identification. Significantly altered proteins were validated in independent biologic replicates by immunoblotting. Survival analyses were performed using public gene expression data to interrogate candidate biomarkers that passed immunoblot verification to evaluate the clinical relevance. Results: Among the 1688 proteins identified, 16 were differentially abundant (P b 0.05) between platinum-resistant and -sensitive ovarian cancer cell lines. Approximately 60% of the identified secretome proteins were also found in the human plasma proteome and/or were annotated in the secreted protein database. A number of the significant differential secretome proteins were verified by immunoblot, including COL11A1, which was also found to be associated with worse progression-free survival (PFS) (n = 723, P = 0.0003) and overall survival (OS) (n = 1183, P = 7 × 10− 5), as assessed from publicly available transcript expression data from ovarian cancer tumor specimens (Fig. 1).
Fig. 1. Kaplan–Meier plots for PFS (A) and OS (B) in ovarian cancer patients with low (≤median) or high (N median) tumor expression of COL11A1 assessed from the average of two probes (median = 6.8722). There were 723 women included in the PFS and 1183 women included in the OS analysis.