Distribution and clinical significance of EGFR mutations in phase I non-small-cell lung cancer

Objective To investigate the distribution and clinical significance of EGFR mutations in phase Ⅰ non-smallcell lung cancer(NSCLC).Methods We examined 272 consecutive phase Ⅰ NSCLC patients' tumor samples for EGFR mutations in exons 18,19,20 and 21 using the Amplification Refractory Mutation System(ARMS).Results 154 patients (56.62％)were identified with mutations in the series of 272.Of all the mutations identified,2 (1.3％) were aminoacidic substitutions (G719 S) in exon 18,53 (34.4 ％) were in frame deletions (19-del) in exon 19,6 (3.9 ％) were insertional mutations (20-ins) in exon 19 and 97 (63.9 ％) were aminoacidic substitutions (L858 R) in exon 21.There were 11 patients with coexisting mutations in other exons.The probability of the coexisting resistance mutations (20-ins) in exon 21 was significantly higher than that in exon 19 (P ＜ 0.05).Mutations in adenocarcinoma samples (148/223,66.4％) were more frequent than that in squamous carcinoma(2/40,5％),while mutations in adeno-squamous carcinoma were highest in all histologic types (P ＜ 0.05).Conclusion EGFR mutations in phase Ⅰ NSCLC in Shanghai and surrounding areas were 56.62％.Mutations were more frequent in particular histologic types,e.g.adenocarcinoma and adeno-squamous carcinoma.Exon 19 deletion mutations and the substitution mutation L858R in exon 21 are the most frequent in NSCLC.And the probability of coexisting 20-ins mutations in exon 21 was significantly higher than which in exon 19. Key words: Carcinoma, non-small cell lung ;  Epidermal growth factor receptor