- To explore, preliminarily, the association between expression levels of genes involved in the DNA repair, EGFR (epidermal growth factor receptor), angiogenesis, and 5-FU pathway (i.e., k-ras, TS [Thymidylate Synthase], ERCC-1 [excision repair cross complementing-1), TP [Thymidine phosphorylase], DPD [Dihydropyrimidine dehydrogenase], EGFR, VEGF [vascular endothelial growth factor], and IL-8 [interleukin-8]) and pathologic complete response. (Due to advances in methodology, the translational medicine objectives are being reconsidered. Therefore, results for this objective are not reported)