Studies of monoclonal antibody BL2-10D1 as a marker for the detection of the urothelial origin of tumors.

Background: In previous studies, the authors demonstrated the value of the monoclonal antibody (MoAb) BL2-10D1 in identifying malignant transitional cells. In this study, the authors evaluate the possible diagnostic value of a murine MoAb, BL2-10D1, raised against human bladder cancer in the determination of the urothelial origin of metastases in a series of 29 patients with metastatic bladder or prostatic carcinoma.

Methods: Using an immunoperoxidase method, BL2-10D1 and anti-prostate-specific antigen (anti-PSA) reactivity were studied, using histologic sections from 18 pelvic lymph nodes and 4 other anatomic sites invaded by transitional cell cancer, and from 7 pelvic lymph nodes containing prostatic cancer.

Results: All lymph nodes containing metastases of transitional cell carcinoma were positive with BL2-10D1, whereas all metastases of prostatic cancer were negative; the four instances of distant urothelial metastases were positive with BL2-10D1 MoAb. Conversely, anti-PSA reacted only with prostatic metastases.

Conclusion: Thus, MoAb BL2-10D1 and anti-PSA complement each other in the separation of cancers of prostatic and urothelial origin, and the BL2-10D1 MoAb has potential usefulness in differentiating between urothelial carcinoma and prostate adenocarcinoma. In patients with bladder tumors of uncertain origin, BL2-10D1 may be helpful in confirming that a tumor is a transitional cell carcinoma.