FGFR4 and breast adenocarcinoma: About half of the population carries a homozygous or heterozygous FGFR4-G388R SNV, which has been associated with poor prognosis in various tumor types, such as adenocarcinomas of the breast, prostate, and colon, as well as squamous cell carcinomas and melanomas of the head and neck [22,24,26].