While this observation along with prior work from others supports the notion that FGFR3 activation promotes a luminal phenotype, a previously unresolved question in the field is whether the enrichment of FGFR3-altered tumors in luminal subtypes is driven by an expansion of luminal cells or whether FGFR3 mutations drive a luminal expression pattern across all tumor cells. The gene discussed is FGFR3; the disease is neoplasm.