MUC5AC and neoplasm: Conversely, MUC5AC was predominantly expressed in non-neoplastic lesions, with strong expression observed in 55.2% (n = 16) versus 13.0% (n = 3) of neoplastic cases (p < 0.001). MUC1 demonstrated high diagnostic performance for neoplasia (sensitivity 95.7%, specificity 75.9%), while MUC5AC showed moderate performance (sensitivity 69.6%, specificity 72.4%).