LFA-1 expression on exocrine glands as a potential novel marker of malignant disease.

The lymphocyte function associated antigen 1 has been found only on leukocytes and lymphoid tissues; however, the expression of lymphocyte function associated antigen 1 on nonhematopoietic cells has not been reported previously. In this study, immunohistochemical expression of lymphocyte function associated antigen 1 was examined on various tissues from 35 patients with malignant diseases and 36 patients with benign diseases including benign tumors. The expression of lymphocyte function associated antigen 1 was found on various exocrine tissues (eg, gastric glands, bronchial epithelium, alveolar epithelium, duodenal glands, bile ducts, pancreatic acini, and salivary glands) uninvolved by tumor in patients with malignant diseases. Localization of lymphocyte function associated antigen 1 was limited to the exocrine glands and differed from tissue-infiltrating leukocytes. The expression of lymphocyte function associated antigen 1 on exocrine tissues was confirmed in all 35 cases of malignant diseases that were examined. These included a wide spectrum of carcinomas and hematopoietic tumors. In contrast, none of the 36 cases with benign diseases examined expressed lymphocyte function associated antigen 1 on their exocrine glands. These results indicate a strong correlation between lymphocyte function associated antigen 1 expression on exocrine glands and malignant disease. The expression of lymphocyte function associated antigen 1 on nonhematopoietic cells was further confirmed in nonhematopoietic cell lines. Two of 19 nonhematopoietic cell lines (MKN45 and PANC-1; exocrine gland cell lines) examined expressed lymphocyte function associated antigen 1 on both cell surface and cytoplasm. These results suggested that immunohistochemically defined lymphocyte function associated antigen 1 molecules on nontumorous exocrine gland cells are a potential marker for the presence of malignant diseases.