A recent study on gene expression in CPAM also including mucin-encoding genes, found that K-RAS mutations and MUC5AC, CK20, and HER2 expression genes (involved in early lung adenocarcinoma development) were present in all CTM with mucinogenic proliferation, thus supporting the importance of complete surgical resection of CTM because of the possible neoplastic nature of at least type 1 CPAM (50). Here, MUC5AC is linked to lung adenocarcinoma.