Molecular biomarkers of residual disease after surgical debulking of high-grade serous ovarian cancer.

PURPOSE Residual disease following primary cytoreduction is associated with adverse overall survival in patients with epithelial ovarian cancer. Accurate identification of patients at high risk of residual disease has been elusive, lacking external validity and prompting many to undergo unnecessary surgical exploration. Our goal was to identify and validate molecular markers associated with high rates of residual disease. METHODS We interrogated two publicly available datasets from chemonaïve primary high-grade serous ovarian tumors for genes overexpressed in patients with residual disease and significant at a 10% false discovery rate (FDR) in both datasets. We selected genes with wide dynamic range for validation in an independent cohort using quantitative RT-PCR to assay gene expression, followed by blinded prediction of a patient subset at high risk for residual disease. Predictive success was evaluated using a one-sided Fisher exact test. RESULTS Forty-seven probe sets met the 10% FDR criterion in both datasets. These included FABP4 and ADH1B, which tracked tightly, showed dynamic ranges >16-fold and had high expression levels associated with increased incidence of residual disease. In the validation cohort (n = 139), FABP4 and ADH1B were again highly correlated. Using the top quartile of FABP4 PCR values as a prespecified threshold, we found 30 of 35 cases of residual disease in the predicted high-risk group (positive predictive value = 86%) and 54 of 104 among the remaining patients (P = 0.0002; OR, 5.5). CONCLUSION High FABP4 and ADH1B expression is associated with significantly higher risk of residual disease in high-grade serous ovarian cancer. Patients with high tumoral levels of these genes may be candidates for neoadjuvant chemotherapy.