PIK3R1 and colorectal carcinoma: For instance, a PIK3R1 mutation emerged in a patient with a BRAF V600E mutation after dual treatment with cetuximab and vemurafenib, suggesting a possible role in acquired resistance to this therapy [20], whilst PIK3CA and PTEN mutations became detectable in circulating tumor DNA from metastatic CRC patients after treatment with panitumumab [49].