The present invention relates to an in vitro method for diagnosing epithelial ovarian cancer, cervical cancer, endometriosis, clear cell renal carcinoma and / or predisposition to epithelial ovarian cancer in a subject, the method comprising determining in a sample of the subject gene expression level of at least one gene in the MDS 1 and EVI1 complex (MECOM) locus, and / or copy number of at least one gene in the MECOM locus, wherein the level against at least one expression cutoff value and / or copy number against at least one copy number cutoff value are indicative of the subject having epithelial ovarian cancer, cervical cancer, endometriosis, clear cell renal carcinoma and / or a predisposition to epithelial ovarian cancer cervical cancer, endometriosis, clear cell renal carcinoma and / or determining whether the ovarian cancer in the subject is primary or secondary ovarian cancer and / or a risk of the disease progression after surgery treatment, and / or an effectiveness of post-surgery chemotherapy.