Similar findings were observed with sphere formation assays, as erlotinib exerted the strongest effect on EGFR-mutated cells (HCC-827: IC50, <0.01 μM; PC-9: IC50, 0.05 μM; SE, 0.01), followed by BRAF class 3–mutated cells (PDX-ADK-36: IC50, 0.11 μM; SE, 0.02; ADK-14: IC50, 0.34 μM; SE, 0.04) and BRAF class 2–mutated cells (NCI-H1395: IC50, 4.75 μM; SE, 1.63), whereas a remarkably weaker effect was observed in BRAF class 1– (HCC-364: IC50, 12.67 μM; SE, 0.86) and KRAS-mutated cells (ADK-17: IC50, 9.34 μM; SE, 0.46; Fig 3E). Here, KRAS is linked to hepatocellular carcinoma.