In the current study, we clarified for the first time that ARHGAP26 expression is decreased in ovarian cancer tissues compared with adjacent noncancerous ovarian tissues from TCGA and our independent hospital databases, and in ovarian cancer cell lines compared with nonmalignant human ovarian surface epithelial cells, and found that ovarian cancer patients with high ARHGAP26 expression tended to have a poor prognosis, suggesting that ARHGAP26 may act as a tumor suppressor involved in ovarian cancer development. This evidence concerns the gene ARHGAP26 and neoplasm.