Western blot analysis revealed that ASCT2 expression was dramatically reduced in KRAS-mutant CRC cell lines by addition of LY 294002 (PI3K inhibitor) or rapamycin (mTOR inhibitor), which suggested that KRAS signaling may regulate ASCT2 expression in CRC mainly via the PI3–Akt–mTOR pathway (Figure 1d). Here, KRAS is linked to colorectal carcinoma.