Gao and collaborators (Tumour Biol, 2013) have investigated the role of mucin 4 (MUC4) in lung cancer and have concluded that a loss of MUC4 results in epithelial mesenchymal transition via beta-catenin nuclear translocation and that MUC4 expression is correlated with a risk of lymph node metastasis in a cohort of 20 lung adenocarcinoma patients. This surprising analysis is contradictory to most of the scientific knowledge and literature regarding MUC4 contribution in epithelial cancers that is very hardly discussed in their manuscript.