Molecularly, the detection of ERBB2 amplification in 57% (first PCR) and 72% (nested PCR) of patients, with frequencies of 80% and 17% in daughters and 79% and 20% in sisters, respectively (Table 2), underscores the hereditary component of ERBB2-driven breast cancer.21 The gene discussed is ERBB2; the disease is breast carcinoma.