[Immunohistochemical Analysis of Krebs von den Lungen-6 (KL-6) Expression in Lung Tissue in Primary Lung Cancer Patients with High Serum KL-6 Levels].

We investigated sialylated carbohydrate antigen( Krebs von den Lungen-6:KL-6) expression in lung tissue and correlation between the expression and serum KL-6 level in the patients with primary lung cancer. Thirty-four primary lung cancer patients with high serum KL-6 levels( >500 U/ml) were evaluated. A coexistence of interstitial pneumonia (IP) was histopathologically evaluated and an immunohistochemical staining using a mouse anti-human KL-6 antibody (mKL-6) was performed. A multiple regression analysis was also caluculated using a serum KL-6 level as a target variable and the histopathological and immunohistochemical factors (KL-6 expression in cancer tissue and IP tissue, coexistence of IP, tumor size, pathological staging) as descriptive variables. Twenty-two patients (64.7%) were histopathologically concomitant with IP. Cancer tissues were positively stained by mKL-6 in 32 patients (94.1%). Among them, 20 patients were concomitant with IP and all of their cancer tissues were more strongly stained by mKL-6 than IP tissues. Although considerable high rate of lung cancer patients might express the KL-6 in the cancer tissue, we could not reveal the relationship between the expression and serum KL-6 level by a multiple regression analysis. For revealing the mechanism of elevating serum KL-6 level in the patients with lung cancer, more detailed and powerful study is thought to be needed.