Acute/lymphomatous ATLL has frequent alterations of p15 (20%) and p16 (28-67%), while chronic/smoldering ATLL has fewer abnormalities of p15 (0-13%) and p16 (5-26%).
Adult T-cell leukemia (ATL) is a retrovirus-associated leukemia with poor prognosis and often has deletions of the p16INK4a and p15INK4b genes on chromosome 9p21.
In hematological malignancies, homozygous deletions of p16ink4a and p15ink4b occur frequently in acute lymphoblastic leukemia (ALL) (14-40%), lymphoid type blast crisis of chronic myeloid leukemia (CML), and adult T cell leukemia (ATL), but p16ink4a deletions are more frequent than p15ink4b deletions, and hemizygous deletions of either p16ink4a and p15ink4b are rare.