Similarly, knocking down the melanotic tumor suppressors ddb1 or DREF by RNAi in several non-immune tissues did not induce melanotic masses [42,50], and HopTuml or a dominant negative form of GCM induced melanotic masses when ectopically expressed respectively in blood cells or in the fat body, but not in other tissues [31,64,65]. The gene discussed is DDB1; the disease is neoplasm.