Through a comprehensive analysis in large-scale datasets, we identified consistent expression levels of MUC4 in pan-cancer using independent datasets via Oncomine and GEPIA2, which showed that MUC4 expression compared with normal samples was upregulated in cervical cancer, lung cancer, and pancreatic cancer, while it was downregulated in head and neck cancer and prostate cancer. This evidence concerns the gene MUC4 and lung cancer.