MET and non-small cell lung carcinoma: Müller-Tidow and his colleagues identified the expression of 56 RTKs in primary NSCLC tumors and found that 33 RTKs are expressed at the mRNA level in 25% samples (Müller-Tidow et al., 2005), indicating that those RTKs may function as an alternatives to EGFR signal pathway in NSCLC, such as cMet, Axl, IGF-1R, and PDGFR.