ERBB2 and neoplasm: However, Nakamura et al reported clinical activity with P+T in both patients with CRC with ERBB2 amplification on tissue testing and those treated based on ctDNA amplification on ctDNA, suggesting that ERBB2 amplification on ctDNA is actionable.41 Thus taken together with our data, ERBB2 amplification on ctDNA is actionable, but lack of ERBB2 amplification on ctDNA does not rule out ERBB2 amplification on tumor analysis.