VTCN1 and ovarian cancer: Diverse methods have been used to develop tumor biomarkers for ovarian cancer: abnormal DNA methylation or BRCA1/BRCA2 gene mutations through gene chip technology [24,25], serum proteomics [26], autoantibodies sequence with immunohistochemistry [27], B7-H4 (one of the T cell costimulatory molecule B7 family) [28], and lysophosphatidic acid [29].