Risk Factors for Rectal Cancer and Methylenetetrahydrofolate Reductase Polymorphisms in a Population in Northeast Thailand

Peechanika Chopjitt,Kirati Poomphakwaen,Supannee Promthet,Shinkan Tokudome,Surapon Wiangnon,Chamsai Pientong,Tipaya Ekalaksananan,Nopparat Songserm

doi:10.7314/apjcp.2012.13.8.4017

Abstract

Polymorphisms in methylenetetrahydrofolate reductase (MTHFR) are known to be associated with predisposition for certain cancers. This study aimed to evaluate the effects of lifestyle factors, family history and genetic polymorphisms in MTHFR C677T and A1298C on rectal cancer risk and possible interactions with lifestyle factors in Northeast Thailand. A hospital-based case-control study was conducted during 2002-2006 with recruitment of 112 rectal cancer cases and 242 non-rectal cancer patient controls. Information was collected using a structured-questionnaire. Blood samples were obtained for assay of MTHFR C677T and A1298C genotypes by polymerase chain reaction with restriction fragment length polymorphism (PCR-RFLP) techniques. Associations between lifestyle factors, family history and genetic polymorphisms v.s. rectal cancer risk were assessed using logistic regression analysis. Subjects with frequent and occasional constipation had a higher risk (OR adj.=14.64; 95%CI=4.28-50.04 and OR adj.=2.15; 95%CI=1.14-4.06), along with those who reported ever having hemorrhoids (OR adj.=2.82; 95%CI=1.36-5.84) or a family history of cancer (OR adj.=1.90; 95%CI=1.06-3.39). Consumption of a high level of pork was also associated with risk (OR adj.=1.82; 95%CI=1.05-3.15). Interactions were not observed between MTHFR and other risk factors. This study suggested that the risk factors for rectal cancer in the Thai population are bowel habits, having had hemorrhoids, a family history of cancer and pork consumption.

Highlights

Rectal cancer is rare in developing countries, in contrast to the high incidence rates in Europe, North America, Australia and Japan
This study aimed to evaluate the effects of lifestyle factors, family history and genetic polymorphisms in methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C on rectal cancer risk and possible interactions with lifestyle factors in Northeast Thailand
Sriamporn et al (2007), studied lifestyle-related risk factors for colorectal cancer in Northeast Thailand, but since there may be differences between the natural history of colon and rectal cancer, associations with each site individually are of interest

Summary

Introduction

Rectal cancer is rare in developing countries, in contrast to the high incidence rates in Europe, North America, Australia and Japan. The annual agestandardized incidence rates of rectal cancer in Thailand were 3.6 and 2.7 per 100,000 in males and females, respectively (Khuhaprema et al, 2007). Songkhla, Chiang Mai and Bangkok had the highest incidence rates in females with the ASR of 3.6, 3.6 and 3.3, respectively (Khuhaprema et al, 2007). This study aimed to evaluate the effects of lifestyle factors, family history and genetic polymorphisms in MTHFR C677T and A1298C on rectal cancer risk and possible interactions with lifestyle factors in Northeast Thailand. Associations between lifestyle factors, family history and genetic polymorphisms v.s. rectal cancer risk were assessed using logistic regression analysis. Conclusions: This study suggested that the risk factors for rectal cancer in the Thai population are bowel habits, having had hemorrhoids, a family history of cancer and pork consumption

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