67-KILODALTON LAMININ RECEPTOR EXPRESSION CORRELATES WITH WORSE PROGNOSTIC INDICATORS IN NONSMALL CELL LUNG CARCINOMAS

Tumor samples obtained from 72 patients resected for non-small cell lu ng cancer were stained immunohistochemically using an immunoperoxidase method and the MLuC5 monoclonal antibody specific for the 67-kDa lami nin receptor, Sixty-one of 72 patients (84.7%) displayed a MLuC5-posit ive reaction, which was usually localized in both the inner surface of the plasmatic membranes and the cytoplasm of neoplastic cells. When w e compared the laminin receptor expression with clinicopathological an d biological parameters such as histotype, grading, T status, N status , ploidy, proliferative activity, vessel invasion, and p53 protein acc umulation, the following results were observed: (a) the mean expressio n of the receptor was higher in the group of patients with metastatic nodal involvement than in those with uninvolved lymph nodes (P=0.02); (b) a high Ki-67 score (>13% of positive cells) was observed in tumors with a higher mean value of laminin receptor (P=0.004); (c) the tumor s harboring neoplastic emboli in their vessels showed a higher laminin receptor immunoreactivity (P=0.02); and (d) a borderline association was found between the high mean value of laminin receptor immunopositi vity and p53 accumulation in neoplastic cell nuclei (P=0.05). Our obse rvations indicate that detection of high tissue levels of 67-kDa lamin in receptor is associated with an invasive phenotype in non-small cell lung cancer and may provide further information in the biological cha racterization of this type of cancer.