HER2 testing is a standard procedure for all new breast cancer diagnoses, as well as in case of tumor progression and/or residual tumor after neoadjuvant treatment (Venetis et al., 2022; Pondé et al., 2018; Viale and Fusco, 2022; Fusco et al., 2022). The gene discussed is ERBB2; the disease is breast carcinoma.