Additionally, the MOUNTAINEER study, a phase II trial of tucatinib, an oral selective inhibitor of HER2/neu receptor, exhibited positive preliminary findings with a notable objective response rate (ORR) of 52.2% and a median response time of 10.4 months, further underscoring the therapeutic potential of HER2-targeted approaches in metastatic carcinoma. This evidence concerns the gene ERBB2 and metastatic carcinoma.