Bladder Cancer Molecular Taxonomy: Summary from a Consensus Meeting

The advent of Omics technologies has been key to the molecular subclassification of urothelial bladder cancer. Several groups have used different strategies to this aim, with partially overlapping findings. The meeting at the Spanish National Cancer Research Center-CNIO was held to discuss such classifications and reach consensus where appropriate. After updated presentations on the work performed by the teams attending the meeting, a consensus was reached regarding the existence of a group of Basal-Squamous-like tumors – designated BASQ – charaterized the high expression of KRT5/6 and KRT14 and low/undetectable expression of FOXA1 and GATA3. An additional tumor subgroup with urothelial differentiation features was recognized whose optimal molecular definition is required. For other subtypes described, more work is needed to determine how robust they are and how to best define them at the molecular level.