Monocyte/Macrophage-directed antibodies Ki-M3 and Ki-M7 detect renal-cell carcinomas

Abstract

Monoclonal antibodies (MAbs) Ki‐M3 and Ki‐M7, which detect cells of the human monocyte/macrophage lineages, were tested using immunohistochemistry on a series of benign and malignant human tumors (n = 43). Positive staining was detected in all renal‐cell carcinomas (n = 19 positive for both Ki‐M3 and Ki‐M7), a few cases of breast carcinoma (n = 6 for Ki‐M3; n = 2 for Ki‐M7), in 1 case each of prostatic carcinoma (Ki‐M3) and prostatic adenoma (Ki‐M3), and in 1 case of endometriosis (Ki‐M3). In normal human kidney Ki‐M3 and Ki‐M7 reacted with proximal tubules and parts of the distal tubules and with the loop of Henle. The Ki‐M3 and Ki‐M7 MAbs proved useful in detecting renal‐cell carcinomas and in distinguishing these tumors and their metastases from morphologically similar neoplasms: in addition, our study further hints that renal cell carcinomas are derived from tubular epithelial cells.