Expression Profiling of Rectal Tumors Defines Response to Neoadjuvant Treatment Related Genes Palma Carazo, Pablo Cano Gutiérrez, Carlos Conde Muíño, Raquel Comino Pardo, Ana Bueno Laraño, Pablo Ferrón Orihuela, José Antonio Cuadros Celorrio, Marta Eugenia Cancer treatment Gene expression Microarrays Rectal cancer Gene amplification Genetic networks Messenger RNA Surgical oncology To date, no effective method exists that predicts the response to preoperative chemoradiation (CRT) in locally advanced rectal cancer (LARC). Nevertheless, identification of patients who have a higher likelihood of responding to preoperative CRT could be crucial in decreasing treatment morbidity and avoiding expensive and time-consuming treatments. The aim of this study was to identify signatures or molecular markers related to response to pre-operative CRT in LARC. We analyzed the gene expression profiles of 26 pre-treatment biopsies of LARC (10 responders and 16 non-responders) without metastasis using Human WG CodeLink microarray platform. Two hundred and fifty seven genes were differentially over-expressed in the responder patient subgroup. Ingenuity Pathway Analysis revealed a significant ratio of differentially expressed genes related to cancer, cellular growth and proliferation pathways, and c-Myc network. We demonstrated that high Gng4, c-Myc, Pola1, and Rrm1 mRNA expression levels was a significant prognostic factor for response to treatment in LARC patients (p<0.05). Using this gene set, we were able to establish a new model for predicting the response to CRT in rectal cancer with a sensitivity of 60% and 100% specificity. Our results reflect the value of gene expression profiling to gain insight about the molecular pathways involved in the response to treatment of LARC patients. These findings could be clinically relevant and support the use of mRNA levels when aiming to identify patients who respond to CRT therapy. 2015-02-25T14:09:30Z 2015-02-25T14:09:30Z 2014 info:eu-repo/semantics/article Palma, P.; et al. Expression Profiling of Rectal Tumors Defines Response to Neoadjuvant Treatment Related Genes. Plos One, 9(11): e112189 (2014). [http://hdl.handle.net/10481/34958] 1932-6203 http://hdl.handle.net/10481/34958 10.1371/journal.pone.0112189 eng http://creativecommons.org/licenses/by-nc-nd/3.0/ info:eu-repo/semantics/openAccess Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License Public Library of Science (PLOS)