These cases also had been dyed IHC by Benchmark with antibodies against EGFR specific protein (deletion specific antibodies in exon 19 E746-A750 and L585R point mutations in exon 21), and calculated based on the intensive staining of cytoplasmic membrane with 10% cutoff point of tumor cells as follows: 0: no staining is observed, or membrane staining < 10% of tumor cells; 1+: a faint / barely perceptible membrane staining > 10% of tumor cells; 2+: a weak to moderate complete membrane staining; 3+: a strong complete membrane staining; The cases were considered postitive: 1+; 2+; 3+; Negative cases: 0; The results of specific IHC and gene sequencing were compared.