Shorter EGFR Dinucleotide Repeat Length Predicts Better Response of Patients with Advanced Non-small Cell Lung Cancer to EGFR Tyrosine Kinase Inhibitor

The purpose of this study is to evaluate the association between intron 1 CA-repeat polymorphisms of the epidermal growth factor receptor gene ( EGFR ) and the clinical outcome of Chinese patients with advanced non-small cell lung cancer (NSCLC) treated with EGFR tyrosine kinase inhibitors (TKIs). We genotyped the intron 1 CA-repeat genetic polymorphisms of EGFR in 84 Chinese patients with NSCLC. The relationship between the length of the CA repeats and EGFR mutations in exons 18–21 in the 84 patients was elucidated. We then analyzed the association between the length of the CA repeats and the clinical outcome of EGFR-TKI-treated patients with NSCLC. EGFR mutations in exon 19 were significantly associated with shorter CA repeats. Patients with shorter CA repeats had a significantly longer progression-free survival with EGFR-TKI treatment than those with longer CA repeats. Our results suggest that shorter CA repeats in intron 1 of EGFR are associated with EGFR mutations and the clinical outcomes of TKI-treated patients with NSCLC.