Detection of the c‐myc Gene Product in Urinary Bladder Cancer

Abstract

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.

Expression of tumour-suppressor gene Rb, apoptosis-suppressing protein Bcl-2 and c-Myc have no independent prognostic value in renal adenocarcinoma

“…These results suggest that the relationship between cell proliferation and expression of c-myc is not clear-cut and other regulatory mechanisms are probably involved. The present results confirm previous results in that poor histological differentiation and expression of c-myc are interrelated (Kotake et al, 1990;Yamaguchi et al, 1992;Lanigan et al, 1993). Stage of disease and expression of Myc were not interrelated, which is at variance with previous results in renal adenocarcinomas (Lanigan et al, 1993).…”

“…Analyses based on paraffin-embedded tissues have found Myc positivity in the cytoplasm and in the nucleus (Kotake et al, 1990;Melhem et al, 1992). This altered cellular distribution is probably related to dislocation of Myc proteins related to fixation and processing of the tissue sections, or they may be less tightly associated with nucleus in malignant cells.…”

“…Myc proteins are normally bound to nuclear matrix proteins (Waitz and Loidl, 1991), and analyses based on frozen tissue sections have demonstrated Myc proteins usually in the cell nucleus (Kotake et al, 1990;Melhem et al, 1992). Analyses based on paraffin-embedded tissues have found Myc positivity in the cytoplasm and in the nucleus (Kotake et al, 1990;Melhem et al, 1992).…”

Tumour cells surviving in vivo cisplatin chemotherapy display elevated c-myc expression

“…Activation of c-myc has been associated with tumours of the breast (Watson et al, 1993), colon , ovary (Tashiro et al, 1992) and squamous cell carcinomas (Ogunbiyi et al, 1993). Significantly, c-myc gene activation has been correlated with poor clinical prognosis for aggressive tumours including bladder cancer (Kotake et al, 1990) and human non-small-cell lung carcinoma (Volm et al, 1993).…”

Over-expression and amplification of the c-myc gene in human urothelial carcinoma

“…In urothelial carcinoma of the bladder, the issue is not as clear. Many advanced urothelial carcinomas become positive in immuno-histochemistry, whereas Myc protein is not usually detectable in normal urothelium (Masters et al, 1988;Kotake et al, 1990;Schmitz-Dräger et al, 1996). In accord with its presumed biochemical function, myc expression as detected by immuno-histochemistry correlated well with cell proliferation (Lipponen, 1995).…”