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Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jun 7, 2015; 21(21): 6470-6478
Published online Jun 7, 2015. doi: 10.3748/wjg.v21.i21.6470
Different treatment strategies and molecular features between right-sided and left-sided colon cancers
Hong Shen, Jiao Yang, Qing Huang, Meng-Jie Jiang, Yi-Nuo Tan, Jian-Fei Fu, Li-Zhen Zhu, Xue-Feng Fang, Ying Yuan
Hong Shen, Jiao Yang, Qing Huang, Meng-Jie Jiang, Yi-Nuo Tan, Jian-Fei Fu, Li-Zhen Zhu, Xue-Feng Fang, Ying Yuan, Department of Medical Oncology, 2nd Hospital of Zhejiang University School of Medicine, Hangzhou 310009, Zhejiang Province, China
Author contributions: Shen H directed the study and drafted the manuscript; Yang J co- drafted the manuscript; Huang Q, Jiang MJ, Tan YN, Fu JF and Zhu LZ reviewed and edited the whole manuscript; Fang XF and Yuan Y designed the study, co-supervised field activities, and revised the manuscript critically for important intellectual content.
Supported by Grants from Key Projects in the National Science and Technology Pillar Program during the Twelfth Five-year Plan Period, No. 2014BAI09B07; and grants from the National Natural Science Foundation of China, No. 81101580 and No. 81201640.
Conflict-of-interest: All authors declare no conflicting interests, including but not limited to, commercial, personal, political, intellectual, or religious interests related to the article.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Ying Yuan, Professor, Department of Medical Oncology, 2nd Hospital of Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou 310009, Zhejiang Province, China. yuanying1999@zju.edu.cn
Telephone: +86-571-87784795 Fax: +86-571-87767088
Received: January 27, 2015
Peer-review started: January 27, 2015
First decision: February 10, 2015
Revised: February 24, 2015
Accepted: March 31, 2015
Article in press: March 31, 2015
Published online: June 7, 2015
Abstract

The colon is derived from the embryological midgut and hindgut separately, with the right colon and left colon having different features with regards to both anatomical and physiological characteristics. Cancers located in the right and left colon are referred to as right colon cancer (RCC) and left colon cancer (LCC), respectively, based on their apparent anatomical positions. Increasing evidence supports the notion that not only are there differences in treatment strategies when dealing with RCC and LCC, but molecular features also vary between them, not to mention the distinguishing clinical manifestations. Disease-free survival after radical surgery of both RCC and LCC are similar. In the treatment of RCC, the benefit gained from adjuvant FOLFIRI chemotherapy is superior, or at least similar, to LCC, but inferior to LCC if FOLFOX regimen is applied. On the other hand, metastatic LCC exhibits longer survival than that of RCC in a palliative chemotherapy setting. For KRAS wild-type cancers, LCC benefits more from cetuximab treatment than RCC. Moreover, advanced LCC shows a higher sensitivity to bevacizumab treatment in comparison with advanced RCC. Significant varieties exist at the molecular level between RCC and LCC, which may serve as the cause of all apparent differences. With respect to carcinogenesis mechanisms, RCC is associated with known gene types, such as MMR, KRAS, BRAF, and miRNA-31, while LCC is associated with CIN, p53, NRAS, miRNA-146a, miRNA-147b, and miRNA-1288. Regarding protein expression, RCC is related to GNAS, NQO1, telomerase activity, P-PDH, and annexin A10, while LCC is related to Topo I, TS, and EGFR. In addition, separated pathways dominate progression to relapse in RCC and LCC. Therefore, RCC and LCC should be regarded as two heterogeneous entities, with this heterogeneity being used to stratify patients in order for them to have the optimal, current, and novel therapeutic strategies in clinical practice. Additional research is needed to uncover further differences between RCC and LCC.

Keywords: Colon cancer, Right, Left, Survival, Molecular

Core tip: The colon is derived from the embryological midgut and hindgut separately, with the right colon and left colon having different features with regards to anatomical and physiological characteristics. Based on the location, colon cancers are referred to as either right colon cancer (RCC) or left colon cancer (LCC), respectively, with both having distinct clinical manifestations. Increasing evidence supports the notion that differences exist in terms of sensitivity to adjuvant, palliative, and targeted treatments between RCC and LCC. In further analysis, significant varieties exist at the molecular level between RCC and LCC. Therefore, RCC and LCC should be regarded as two heterogeneous entities. Clinically, this heterogeneity is highly beneficial in therapeutic decision-making.