Genomic Sequencing Examination of 733 HER2-amplified primary and metastatic breast tumours disclosed considerable enrichment of mutations that activate RAS–MAPK signalling in Sophisticated tumours dealt with with prior anti-HER2 therapies121. These mutations, like NF1 and HER2 activating mutations, lead to resistance to tucatinib and neratinib. In BC, pCR soon after NACT https://www.directivepublications.org/journal-of-clinical-breast-cancer/