Figure 1

Rectal biopsy figures show typical prostate cancer with rectal involvement. a and b. Specimens of rectal biopsy show poorly differentiated adenocarcinoma infiltrating rectal mucosa (hematoxylin-eosin, original magnification × 40 and × 400). c. Immunohistochemical staining with anti-PSA antibody, showing that tumor cells were positive while normal colonic glands were negative (original magnification × 400); d. Immunohistochemical staining with anti-CEA antibody, showing that tumor cells were negative while normal colonic glands were positive (original magnification × 400).