KRAS and cancer: NRAS is closely to KRAS, which also a member of RAS gene23, although NRAS gene mutation is rare in CRC, approximately 2.2–4.19%16, 22, 24, it appears a valuable prognostic biomarker in anti-EGFR MoAbs therapy for mCRC patients5, 25, then NRAS status for indicating prognosis should be further confirmed in early stage cancers.