Increased expression of the laminin receptor in human colon cancer.
 It has been proposed that among the various cell-surface proteins capable of interacting with laminin, the 67-kd high-affinity laminin receptor plays a crucial role during tumor invasion and metastasis.
 In this study, the expression of laminin-receptor-precursor messenger RNA (mRNA) and 67-kd protein was analyzed in human colon adenocarcinoma.
 In 22 of 23 patients with colon cancer, we found a 2- to 23-fold increase in levels of laminin-receptor-precursor mRNA in the cancer tissues compared with those in matched normal adjacent colonic mucosa.
 In 10 of 11 cases studied, the level of 67-kd laminin receptor, detected by affinity-purified anti-laminin-receptor synthetic peptide antibodies on immunoblots of matched tumor and normal tissue extracts, was higher in the colon carcinoma tissue.
 Immunodetection of laminin receptor in tissue sections using anti-laminin-receptor-peptide antibodies confirmed that the increased expression of laminin receptor was specifically associated with the cancer cells.
 In a series of 72 paraffin sections of colon lesions, we observed a correlation between the expression of the laminin receptor and the Dukes' classification.
 Our observations indicate that increased expression of laminin-receptor-precursor mRNA is associated with enhanced levels of the 67-kd laminin receptor as well as with the invasive phenotype of colon carcinoma.
 Detection of this metastasis-associated gene product may be a valuable adjunct in the evaluation of human colon cancer.
