We identified that the expression levels of the checkpoint genes, including PDCD1, CD274, PDCD1LG2, CTLA4, CD86, CD80, LAG-3 and TIM-3 were remarkably higher in subtype 3, indicating that subtype 3 may be linked to the intrinsic immune response of ovarian cancer. This evidence concerns the gene CTLA4 and ovarian carcinoma.