IHC analysis with an anti-MUC5AC antibody (45M1 clone) was performed on normal (n = 10), primary lung adenocarcinoma (n = 10), primary lung squamous cell carcinoma (n = 29), squamous cell carcinoma brain metastasis (n = 13) and adenocarcinoma brain metastasis (n = 11) tissues. Here, MUC5AC is linked to squamous cell carcinoma.