Radiation effects on morphology and CD44 expression in primary human prostate cancer (case 5). Compared to the prostate cancer before radiotherapy (A), radiation-induced atypia, pleomorphic hyperchromatic nuclei, and pale voluminous cytoplasm are evident in the tumor biopsied after radiation (B). No CD44-expressing tumor cells were detected in the prostate cancer tissues before radiation (C), but is strongly expressed at the cell membrane of tumor cells after radiation (D). (A and B, hematoxylin-eosin stain; C and D, immunohistochemistry; original magnification, x400.)