Very recently, germline mutational status of the DNA-repair genes breast cancer 1 and 2 (gBRCA1/2) has been shown to be predictive of response to the poly(ADP-ribose)-polymerase 1 (PARP1)-inhibitor olaparib in early-stage HER2-negative breast cancer patients (Tutt et al., 2021). Here, ERBB2 is linked to breast cancer.