LETMD1 is involved in tumorigenesis and may function as a negative regulator of the TP53/p53. It is found in kidney, liver, skeletal muscle, heart and brain and is over-expressed in various tumors including leukemia, lymphoma, and carcinomas of the breast, kidney, ovary, stomach, colon and uterine cervix. There are six isoforms.HCCR-2 that was overexpressed in various human tumors including leukemia, lymphoma, and carcinomas of the breast, kidney, ovary, stomach, colon, and uterine cervix. Ectopic expression of HCCR-2 resulted in direct tumorigenic conversions of NIH/3T3 and Rat1 fibroblasts. HCCR-2 probably represents a new oncogene that is related to tumorigenesis, functioning as a negative regulator of the p53 tumor suppressor.