Differential expression of RAB9B in human epithelial ovarian cancer.
Epithelial ovarian cancer (EOC) is the most lethal gynecologic cancer (1). We performed discovery of genes associated with epithelial ovarian cancer and of the high-grade serous ovarian cancer (HGSC) subtype, using published microarray data (2, 3) to compare global gene expression profiles of normal ovary or fallopian tube with that of primary tumors from women diagnosed with epithelial ovarian cancer or HGSC. We identified the gene encoding RAB9B, member RAS oncogene family, RAB9B, as among the genes whose expression was most different in epithelial ovarian cancer as compared to the normal fallopian tube. RAB9B expression was significantly lower in high-grade serous ovarian tumors relative to normal fallopian tube. RAB9B expression correlated with progression-free survival in patients with p53 mutant ovarian cancer. These data indicate that expression of RAB9B is perturbed in epithelial ovarian cancers broadly and in ovarian cancers of the HGSC subtype. RAB9B may be relevant to pathways underlying ovarian cancer initiation (transformation) or progression.