STUDIES OF MONOCLONAL-ANTIBODY BL2-10D1 AS A MARKER FOR THE DETECTIONOF THE UROTHELIAL ORIGIN OF TUMORS

Background. In previous studies, the authors demonstrated the value of the monoclonal antibody (MoAb) BL2-10D1 in identifying malignant tran sitional cells. In this study, the authors evaluate the possible diagn ostic value of a murine MoAb, BL2-10D1, raised against human bladder c ancer 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 invade d by transitional cell cancer, and from 7 pelvic lymph nodes containin g prostatic cancer. Results. All lymph nodes containing metastases of transitional cell carcinoma were positive with BL2-10D1, whereas all m etastases of prostatic cancer were negative; the four instances of dis tant urothelial metastases were positive with BL2-10D1 MoAb. Conversel y, 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 a nd prostate adenocarcinoma. In patients with bladder tumors of uncerta in origin, BL2-10D1 may be helpful in confirming that a tumor is a tra nsitional cell carcinoma.