MUC5B and neoplasm: Other signature genes (TP63, CERS3, CSTA, CLCA2, DSC3 and DSG3) upregulated in C1 tumours are also markers of the squamous-like subtype, while further columnar-like marker genes (MUC5B and RGL3) are upregulated in C2 tumours (Supplementary Data 3).