A strong association of the HER2 codon 655 AG with cardiotoxicity was also noted by Gómez Peña et al., 2015 [228], compared to the homozygous allele (95% CI (1.20–12.57), p = 0.024) in HER2 breast cancer patients treated with trastuzumab. This evidence concerns the gene ERBB2 and breast cancer.