KRT18 and neoplasm: Neither the ‘mRNA-C3’ nor the keratin-low iCluster were associated with poor prognosis in TCGA’s analysis and given the increased expression of a subset of keratin genes (including KRT7, KRT8 and KRT18) in TCGA tumours C2 according to our classification (Fig. 3), we decided against adopting the keratin-high / keratin-low nomenclature for our clusters.