Precancerous and cancerous lesions are detected in aged male heterozygous Men1 mutant mice. Haematoxylin and eosin staining of a normal lateral prostate lobe from a 24-month-old Men1
+/+ mouse (A) and precancerous or cancerous lesions observed in prostate glands from heterozygous Men1 mutant mice (B-F). (B) mPIN found in the anterior prostate with a signet ring variant: cytoplasmic vacuoles displacing the cell nuclei (21-month-old mouse). (C) In situ carcinoma in the dorsal prostate (26-month-old mouse). (D) Adenocarcinoma in the anterior prostate with branching and papillary infolding (23-month-old mouse). (E) Differentiated invasive adenocarcinoma in the lateral prostate (in situ component) from a 23-month-old mouse. (F) Invasive component of the same lesion as in (E) showing invasion to the prostatic connective tissue. Insets show a magnified view of a part of the prostate glands. Scale bars, 50 μm.