In colon cancer, human promyelocytic, and in certain chemoresistant side populations of cancer stem cells, regulation of miR-21 (under different treatments) was AP-1-mediated, which is in agreement with our findings that the JNK-1/c-Jun/miR-21 pathway is activated in cisplatin resistant ovarian cancer cells. The gene discussed is MAPK8; the disease is malignant colon neoplasm.