Abstract: The present invention was aimed at reducing transcription activating activity of MITF-M to inhibit production of BCL2 gene product and thereby to allow treatment and/or prevention of melanoma The present invention provided a method of inhibiting production of BCL2 gene product and an agent for inhibiting the same, which inhibit binding of protein selected from a group consisting of HLF, ELK4 and CLOCK to MITF-M, a method of inducing cell death of melanoma cells, an agent for inducing the same, an agent for treating and/or preventing diseases accompanied by enhanced production of BCL2 gene product, such as melanoma, a method of treating and/or preventing the diseases, a method of identifying any one of the following compounds: a compound that inhibits the aforementioned binding; a compound that inhibits production of BCL2 gene product; and a compound that increases sensitivity of melanoma to melanoma drugs, as well as a reagent kit.