PTTG1 and leukemia: In contrast, PTTG is highly expressed in a variety of human primary tumors as well as tumor cell lines including tumor of the ovary, lung, testis, kidney, colon, thyroid, pituitary, liver, adrenal, breast, prostate, melanoma, leukemia, and lymphoma [6-9,12-19], suggesting that PTTG may be involved in tumorigenesis.