Abstract
4647 Background: Lapatinib (GW572016) is a dual tyrosine kinase inhibitor of EGFR and HER2. In SWOG0413 trial, advanced or metastatic gastric cancer patients were treated with lapatinib. In this study, we investigated whether gene expressions and polymorphisms of EGF and angiogenesis pathway genes were associated with clinical outcome in the patients enrolled in SWOG0413 trial. Methods: A total of 46 patients were enrolled in SWOG0413 trial and treated with lapatinib. Blood and tissue samples were available from 42 and 37 patients, respectively. RT-PCR was performed for intratumoral gene expression levels of EGFR, HER2, VEGF, IL-8, COX2 and cyclin D1 genes. We also analyzed 8 polymorphisms in the EGF, EGFR, HER2, VEGF, IL-8, COX2 and cyclin D1 genes by PCR-RFLP. Results: Patients who have lower IL-8 [median overall survival (OS), 6 vs 3 months, p=0.03] and higher HER2 (6 vs 3 months, p=0.005) gene expression levels showed better OS. According to gene polymorphisms, patients who have A allele of IL-8 T251A polymorphism showed improved OS (A/A, 10 months vs T/A, 5 months vs T/T 3 months, p=0.04). And patients with A allele of IL-8 T251A and T allele of VEGF C936T polymorphisms showed better response rates (p<0.01, p<0.01, respectively). All other polymorphisms and gene expressions did not show significant association with clinical outcome. Conclusions: Our results suggest that intratumoral gene expression levels of HER2 and IL-8 and polymorphism in IL-8 are potential molecular predictors for survival in patients with advanced or metastatic gastric cancer treated with lapatinib. And polymorphisms in IL-8 and VEGF genes may be potential markers in predicting response in this population. A larger prospective study is needed to validate and confirm these preliminary findings. [Table: see text]
Published Version
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