KRT5 and urothelial carcinoma: Accumulating evidence suggests that minor subpopulations of basal cells, characterised by the expressions of keratin 5 (KRT5) and keratin 14 (KRT14), possess self-renewal capacity and give rise to all cell types of the urothelium during natural and injury-induced regeneration processes, which represents the cellular origins of urothelial carcinoma (Shin et al., 2011; Papafotiou et al., 2016).