PIM1 and prostate intraepithelial neoplasia: In contrast to pim1 grafts, all of the c-myc and c-myc/K67M grafts showed multiple foci of high-grade prostate intraepithelial neoplasia (PIN), a putative precursor lesion for prostate carcinoma, but none of them showed evidence of invasive cancer after 42 days (32).