The phase II Japanese TRIUMH study also demonstrated the promising anti-tumor activity of pertuzumab plus trastuzumab in treatment-refractory metastatic CRC patients with ERBB2 amplification (IHC3+ or FISH-positive) in tissue and/or circulating tumor DNA (ORRs 30% and 28% in patients with HER2 amplification confirmed by tumor tissue and ctDNA, respectively) [120]. Here, ERBB2 is linked to colorectal carcinoma.