Previous studies authenticate that the hypermethylation of ALX4 gene is found in colorectal cancer and bladder cancer tissues, which can be used as a candidate biomarker (33, 34); ALX4 expression is decreased in breast cancer tissues and cells, and it inhibits the progression of breast cancer by interfering with Wnt/β-catenin pathway (35); in ovarian cancer, ALX4 promotes invasion and EMT of ovarian cancer cells by raising SLUG expression (36); ALX4 expression is declined in HCC tissues, and ALX4 overexpression impedes the multiplication, invasion, and EMT process of HCC cells (37). Here, ALX4 is linked to ovarian cancer.