Substitutions in the KRas oncogene determine protein behavior: Implications for signaling and clinical outcome.

Mutant KRAS (mut-KRAS) is present in 30% of all human cancers and plays a critical role in cancer cell growth and resistance to therapy. There is evidence from colon cancer that mut-KRAS is a poor prognostic factor and negative predictor of patient response to molecularly targeted therapy. However, evidence for such a relationship in non small cell lung cancer (NSCLC) is conflicting. KRAS mutations are primarily found at codons 12 and 13, where different base changes lead to alternate amino acid substitutions that lock the protein in an active state. The patterns of mut-KRas amino acid substitutions in colon cancer and NSCLC are quite different, with aspartate (D) predominating in colon cancer (50%) and cysteine (C) in NSCLC (47%).

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Ihle NT, Byers LA, Kim ES, Saintigny P, Lee JJ, Blumenschein GR, Tsao A, Liu S, Larsen JE, Wang J, Diao L, Coombes KR, Chen L, Zhang S, Abdelmelek MF, Tang X, Papadimitrakopoulou V, Minna JD, Lippman SM, Hong WK, Herbst RS, Wistuba II, Heymach JV, Powis G