The 17-1A antigen is expressed on primary, metastatic and disseminated non-small cell lung carcinoma cells

In view of the high incidence of early distant tumor relapses in apparently completely resected (R0, M0) non-small cell lung cancer (NSCLC), there is a need for an adjuvant therapy. Considering the low tumor burden in these patients, an adjuvant therapy with monoclonal antibodies (i.e., the 17-1A MAb) might be appropriate. The purpose of our study was to test whether the 17-1A antigen is expressed on primary and metastatic NSCLC carcinoma cells. Using immunohistochemistry, the expression of 17-1A was analysed in primary tumors (n = 60) and in lymph node metastases (n = 7) of patients with NSCLC. Additionally, we investigated in 6 patients the expression of 17-1A on disseminated tumor cells in the bone marrow, which were detected by the pan-cytokeratin MAb A45-B/B3 using a double-labeling technique. The 17-1A antigen was homogeneously expressed in 47 (78.3%) out of 60 primary NSCLCs. The expression of 17-1A was independent from the tumor histology, the grade of differentiation, and other clinicopathological parameters (ploidy status, TNM-stage). Lymph node metastases were positive in 4 (57.4%) out of 7 cases. The double-labeling experiments demonstrated that 17-1A is coexpressed on disseminated tumor cells in the bone marrow in 5 (83%) out of 6 patients. The 17-1A antigen is expressed on the majority of primary, metastatic, and disseminated NSCLC cells. Patients with 17-1A-positive tumors might benefit from an adjuvant therapy with MAb 17-1A after completely resected NSCLC.