In addition to the FGF3 locus (int-2 in mice), high-throughput analysis of the MMTV insertional mutagenesis identified an activated FGF pathway in 67% of the mammary tumors with virus common insertion sites near FGFR1 and FGFR2 (Theodorou et al., 2007). This evidence concerns the gene FGF3 and breast cancer.