PIM2 encodes a protooncogene that acts as a serine/threonine protein kinase. Studies determined the encoded protein functions to prevent apoptosis and to promote cell survival. The deduced 334-amino acid sequence of the clone showed 90% identity with the mouse Pim2 protein. Like mouse Pim2, the human protein appears to be a serine threonine kinase. Northern blot analysis detected 2 PIM2 transcripts. A 2.2-kb transcript was expressed in all tissues tested, but most abundantly in hematopoietic tissues, spleen, thymus, and peripheral blood leukocytes, as well as in testis, small intestine, and colon. It was also highly expressed in human leukemic and lymphoma cell lines and a colorectal adenocarcinoma cell line. A 5.0-kb transcript was expressed only in spleen, thymus, small intestine, colon, and in very small amounts in peripheral blood leukocytes.