We initially tested MRE11, RAD50 and NBS1 protein expression in a panel of breast cancer cell lines [MCF-7 (ER+, luminal A), ZR-75-1 (ER+, luminal B), SKBR3 (HER2+), MDA-MB-231 (triple-negative)]. The gene discussed is ERBB2; the disease is breast carcinoma.