TA-MUC1 epitope in non-small cell lung cancer

MUC1 (CD227), an established tumor marker, is expressed on glandular epithelia and on epithelial tumors. Tumor MUC1 differs from normal MUC1 by modified glycan side chains. Recently, a novel carbohydrate-induced conformational tumor-associated MUC1 epitope (TA-MUC1) was described, whose clinical relevance in lung cancer is not known. Eighty-five paraffin embedded tissue sections of non-small cell lung cancer (NSCLC) patients (73% male; mean age 64±9 years) were stained with the monoclonal antibody PankoMab (against TA-MUC1) and compared with the established antibodies E29 and 214D4 regarding prognostic relevance. TA-MUC1 is virtually absent in bronchial epithelium. As shown by multivariate analysis, only staining with PankoMab, but not with E29 or 214D4, was correlated with patients’ survival (p=0.029). Moreover, when regarding interactions of MUC1 antibody staining results and clinico-pathological parameters, patients with lymph node metastasis lacking PankoMab staining were attributed the highest risk by far (Hazard ratio=4.6, 95% CI: 2.1–9.7, p=0.000). In summary, the presence of TA-MUC1 is a favorable prognostic factor in this cohort of NSCLC patients, in particular if lymph node metastases are present. This is in contrast to the results for E29 and 214D4, which recognize less or not glycosylation dependent epitopes. As this is the first report on a well-defined MUC1 epitope associated with improved survival in NSCLC, a more differentiated view on MUC1 may be mandatory.