Double knockout (dKO) studies in our laboratory revealed that p27 [15] and cyclin D2 [16] are important modifiers of the Inha KO phenotype as Inha/Cdkn1b dKOs had accelerated cancer development, whereas Inha/Ccnd2 dKOs had attenuated tumor formation. The gene discussed is CDKN1B; the disease is neoplasm.