Association of Pretherapeutic Expression of Chemotherapy-Related Genes with Response to Neoadjuvant Chemotherapy in Barrett Carcinoma

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Abstract
Purpose: We analyzed pretherapeutic gene expression patterns of patients with locally advanced adenocarcinomas of the esophagus with regard to response to neoadjuvant chemotherapy. Experimental Design: Pretherapeutic, paraffin-embedded, formalin-fixed endoscopic esophageal tumor biopsies of 38 patients with locally advanced esophageal adenocarcinomas (Barrett adenocarcinoma) were included. All patients underwent two cycles of cisplatin and 5-fluorouracil (5-FU) therapy with or without additional paclitaxel followed by abdominothoracal esophagectomy. RNA expression levels of 5-FU metabolism-associated genes thymidylate synthase, thymidine phosphorylase, dihydropyrimidine dehydrogenase, methylenetetrahydrofolate reductase, MAP7, and ELF3, of platinum- and taxane-related genes caldesmon, ERCC1, ERCC4, HER-2/neu, and GADD45, and of multidrug resistance gene MRP1 were determined using real-time reverse transcriptase-PCR. Expression levels were correlated with response to chemotherapy, histopathologically assessed in surgically resected specimens. Results: Responding patients showed significantly higher pretherapeutic expression levels of MTHFR (P = 0.012), caldesmon (P = 0.016), and MRP1 (P = 0.007). In addition, patients with high pretherapeutic MTHFR and MRP1 levels had a survival benefit after surgery (P = 0.013 and P = 0.015, respectively). Additionally, investigation of intratumoral heterogeneity of gene expression of relevant genes (MTHFR, caldesmon, HER-2/neu, ERCC4, and MRP1), verified in nine untreated Barrett adenocarcinomas by examination of five distinct tumor areas, revealed no significant heterogeneity in gene expression indicating that expression profiles obtained from biopsy material may yield a representative genetic expression profile of total tumor tissue. Conclusions: Our results indicate that determination of mRNA levels of few genes may be useful for the prediction of the success of neoadjuvant chemotherapy in individual cancer patients with locally advanced Barrett adenocarcinoma.