Detection of the c-myc gene product in urinary bladder cancer

Expression of the c-myc gene product in urinary bladder cancer was investigated by immunohistochemical staining with anti-c-myc monoclonal antibody (mAb) MYC-1. Positive staining was observed in the cytoplasm, but not in the nucleus in tissues fixed with 10% formalin. On the other hand, positive staining was localized in the nucleus in cryopreserved tissues. Of 34 cryopreserved specimens examined, positive staining with MYC-1 mAb was observed in 1 of 12 (8.3%) of grade 1 (G1), 12 of 15 (80%) of G2 and 6 of 7 (86%) of G3. Positive staining with Ki-67 mAb was observed in 2 of 12 (17%) of G1, 12 of 15 (80%) of G2, and 6 of 7 (86%) of G3. These results suggest that tumors with higher nuclear pleomorphism contain more proliferating cells.