Except for the small insertions or point mutations, some other resistant HER‐2 alterations have also been identified in HER‐2‐positive breast cancer, such as Δ16HER‐2 (a HER‐2 splice variant lacking exon 16) and p95HER‐2 (carboxy‐terminal HER‐2 fragments, mostly known as 611‐CTF; Fig. 2) 53, 54. This evidence concerns the gene ERBB2 and breast cancer.