ABCG2 and serous adenocarcinoma: Because of the increased expression of BCRP, MGMT, and RRM1 identified in serous carcinomas, in theory chemotherapeutic agents such as etoposide, adriamycin, temozolomide, and gemcitabine may be avoided in the treatment of serous tumors that overexpress these biomarkers and considered only for other histologies of ovarian cancer.