We correlated the mutation frequency of MUC4, MUC6, and MUC12 with the non-small-cell lung carcinoma, and identified a distinct mutation frequency in tumor samples from smokers (20%) and non-smokers (6%), which cumulatively designates these MUC genes as diagnostic and prognostic markers in smokers. The gene discussed is MUC6; the disease is non-small cell lung carcinoma.