Targeted therapies currently in clinical use in colorectal cancer include the anti-EGFR monoclonal antibodies cetuximab and panitumumab, alone or with chemotherapy for KRAS wild-type disease; combinations of anti-EGFR monoclonal antibodies with BRAF inhibitors, such as vemurafenib and encorafenib, for colorectal cancers bearing BRAF V600E mutations; and anti-HER2 therapies, including trastuzumab, lapatinib, and tucatinib, for HER2-altered cancers and immune checkpoint inhibitors, such as pembrolizumab and nivolumab, for cancers that display high microsatellite instability (MSI-H). This evidence concerns the gene KRAS and colorectal cancer.