Fig. 2

Prostein immunostaining in cancer. Prostein staining is usually granular, cytoplasmic and predominantly perinuclear (“endoplasmatic reticulum pattern”). The panels show a particularly strong prostein positivity in a Gleason 3 + 3 = 6 carcinoma (A) and a recurrent Gleason 5 + 5 = 10 carcinoma of the prostate (B). Prostein staining of tumor cells is less intense but still significant in samples of mucoepidermoid carcinoma of a salivary gland (C), neuroendocrine tumor of the lung (D), adenocarcinoma of the colon (E), and a muscle-invasive urothelial carcinoma of the urinary bladder (F). A distinct staining of giant cells is seen in samples of a giant cell tumor of the tendon sheet (G) and a pilomatrixoma of the skin (H)