However, because of intratumoral heterogeneity, the inadequate tissue acquired from CNB may not provide complete pathological characteristics of the tumor, causing discordance between cores in 8% of HER2-positive cases and discordance between CNB and surgical pathology results for approximately 26.6% of HER2 status (11, 13, 14). The gene discussed is ERBB2; the disease is neoplasm.