Epidermal growth factor receptor intron 1 (CA)n dinucleotide repeat polymorphism and mutations associated with the responsiveness of molecular targeted therapy in lung cancer

Abstract

e14595 Background: To explore EGFR gene intron 1 (CA)n repeat polymorphism and mutations associated with the responsiveness of molecular targeted therapy in lung cancer. Methods: Both observed groups consisted of 116 somatic specimens of lung cancer and controls consisted of 20 peripheral blood samples were analyzed by direct DNA sequencing of EGFR mutations at exons 18,19,21. Also (CA)n repeat polymorphisms in intron 1 of EGFR from 48 specimens were analyzed. 45 lung cancer patients were followed up. Results: EGFR mutations were found in 24 of 116 somatic specimens (20.69%). Response rate and disease control rate to EGFR TKIs was significantly higher in the patients with EGFR mutations (62.5% vs. 0)(P<0.0l),(100% vs.44.4%) (P<0.05)respectively than those without it in observed groups.In patients harboring EGFR mutations, disease control rate to patients treated with Iressa (100%) was significantly higher than those who never treated with it (40%)(P<0.05). The frequency distribution of EGFR intron 1 (CA)n repeat in 48 specimens was 23(47.9%)low (CA)n repeat(CA≤16)and 25 (52.1%) high repeat(CA>16). There was no significant difference in response rate and disease control rate of EGFR TKIs treatment between low and high (CA)n repeat numbers both in 16 patients with mutations and 18 patients without mutations in observed groups(P>0.05). Conclusions: Somatic mutations of EGFR is a major determinant of EGFR TKIs response in lung cancer. There was no significant difference in response rate and disease control rate of EGFR TKIs treatment between low (CA) n repeat patients and high repeat ones under the consideration of the mutant factor. No significant financial relationships to disclose.