Demonstration of low density lipoprotein receptor in human colonic carcinoma and surrounding mucosa by immunoenzymatic assay.

In order to verify the presence of Low Density Lipoprotein Receptor (LDLR) in cellular membranes isolated from human colonic tissue, samples from the neoplastic colorectum and the normal surrounding mucosa were studied by an enzyme-linked-immunosorbent assay. A monoclonal antibody against the human LDLR was used. The LDLR content revealed a considerable inter-individual variation. In 36 out of 53 cases (68%) there was no LDLR presence in either normal or neoplastic tissue samples. In 5 out of 53 cases (9.4%), LDLRs were detected in both types of tissue samples, in 9 cases out of 53 (17%) LDLRs were present in neoplastic tissue, while in 3 out of 53 cases (5.6%) only in normal mucosa. The anti-LDLR mono-clonal antibody (mAb) binding was significantly higher in neoplastic tissue samples than normal surrounding colonic mucosa ones. Sex, age, body mass index (BMI), serum cholesterol, tumour site, histologic grading and Dukes' stage did not seem to be associated with LDLR presence.