Previous studies described intratumor heterogeneity of HER2 expression between prCRC and BM, documenting discordant HER2 status between primary tumour and matched metastases, both intra and extracranial: in these studies, the impact of HER2 discordance on prognosis is unclear [17, 18]; on the other hand, the indirect weight of the heterogeneity between prCRC and metastases on prognosis is intuitive, because molecular modifications could lead to increased therapeutic chances. Here, ERBB2 is linked to neoplasm.