The immunogen for the anti-human p15 was a his-tagged recombinant full length p15 protein recognizing a 15kDa protein. The p15ink4b tumor suppressor protein shows no cross reactivity with the closely related inhibitors including p16ink4a and p19ink4d. p15ink4b is a specific inhibitor of cdk4/cdk6, and is periodically expressed during cell cycle. Synonyms: hp15, p15 ink4b, Cyclin-dependent kinase 4 inhibitor B, Multiple tumor suppressor 2.