Examples of p14ARF, p53 and Hdm2 immunoreactivity in infiltrating ductal carcinoma of the breast. Immunostaining was performed as described in the Methods section, and nuclei were counterstained with haematoxylin. (a) A tumour showing nuclear p14ARF expression in invasive ductal cancer; (b) a similar nuclear p14ARF positivity in concomitant ductal carcinoma in situ (DCIS). (c) Cytoplasmic p14ARF expression in invasive ductal cancer is representative of similar expression in DCIS. Representative examples of expression of nuclear p53 (d), cytoplasmic p53 (e), and also nuclear Hdm2 (f) and cytoplasmic Hdm2 (g). High-power magnification (×400) (a-g). Insets show higher-power (×1000) views of the same fields.