FGFR1 and breast cancer: Indeed, definition of FGFR1 amplification by FISH technique has been highly variable in the previous studies in lung cancer and breast cancer.[16, 24, 25, 28, 33, 34] Unlike breast cancer, lung SqCC exhibits small-clusters and co-amplifications of FGFR1 and CEN8.[25] Therefore, FGFR1 FISH assay needs to differentiate between true amplification and polysomy.