Moreover, immunohistochemical analysis of needle biopsies obtained before chemotherapy and in the surgically resected tumors after chemotherapy based on doxorubicin and cisplatin found an increase in BCRP expression after pharmacological treatment in all analyzed patients, although it is not clear whether this was due to clonal selection or actual upregulation in individual tumor cells [28]. The gene discussed is ABCG2; the disease is neoplasm.