Lung cancer patients (non-small cell lung cancer, small cell lung cancer): 1. Increased number of CD56+ CD3+ T cells in peripheral blood from lung cancers (NSCLC and SCLC) compared to healthy controls (2.91% in NSCLC, 2.97% in SCLC, and 1.6% in healthy controls) 2. Increased number of CD56+CD3+ T cells in Stage I (9.0%) compared to Stage IV (3.8%) NSCLC patients. Here, NCAM1 is linked to lung cancer.