Siravegna et al. [267] showed how the ctDNA liquid biopsy can identify the different genomic evolution of each metastasis in mCRC, treated with HER2 blockade therapy [trastuzumab and lapatinib on the HER2 Amplification for Colo-rectaL cancer Enhanced Stratification (HERACLES) study]. Here, ERBB2 is linked to cancer.