ERBB2 and breast cancer: In breast cancers, the most prevalent fusion genes were FGFR family genes (total, 0.48%; FGFR2, 0.34%; FGFR1, 0.14%), ErbB family genes (total, 0.47%; EGFR, 0.20%; ERBB2, 0.27%), ALK (0.27%) and ROS1 (0.07%).