Ulex europeus agglutinin I-reactive high molecular weight glycoproteins of adenocarcinoma of distal colon and rectum and their possible relationship with metastatic potential.

A Ulex europeus agglutinin I (UEAI)-reactive glycoprotein(s) with molecular weight higher than 300,000 was detected by direct binding of 125I-labeled UEAI to lysates of rectal or sigmoid colon cancer tissues separated by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. This was the major UEAI-reactive molecule in tumor tissues and different tumors possessed varying reactivities. Very little UEAI binding was detected to lower molecular weight components. Histochemical localization of UEAI confirmed that the UEAI-reactive molecules were mostly localized to the surface of carcinoma cells. A total of 135 fresh tissue samples, including those from adenocarcinoma, villous adenoma, and normal mucosa in surgical specimens (69 patients), were examined to determine the reactivities of UEAI to the high molecular weight component in the tissue extracts. The quantitative binding of 125I-UEAI was compared according to the stage of colorectal cancer at the time of surgery. The relative amount of UEAI-reactive high molecular weight substance was significantly higher in the carcinomas than in normal mucosa. UEAI binding to high molecular weight regions of the polyacrylamide gel was significantly lower in primary colorectal adenocarcinomas from stage C or D patients than in those from stage B1 patients. Therefore, increased expression of the UEAI-reactive molecule was related to transformation of colorectal epithelial cells and decreased expression appeared to be associated with progression and metastatic potential.