Case report: Durable response from tegafur/gimeracil/oteracil (S-1) combined with fruquintinib and sintilimab as a third-line treatment for MSS metastatic colorectal cancer with a BRAF V600E mutation - He, Chunxia; Chi, Jiaxin; Du, Zhihua; Zhuang, Zhenjie; Li, Liuning (Frontiers in Oncology, 2024)