The development of colorectal cancer does not depend on a single factor; it is the result of a complex interaction between genetics, the environment, and the individual lifestyle. Now, a new study led by IDIBELL-ICO researchers has shed light on the specific interaction between genetics and environment in the risk of developing colorectal cancer. Specifically, they have focused on the effect of prolonged exposure to trihalomethanes, a common by-product of the water purification process, on the risk of developing colorectal cancer. According to the results, genetic variants have been identified that could modulate the body’s response to trihalomethanes and influence the risk of developing this cancer.
The research, led by Dr. Víctor Moreno and with Ferran Moratalla as the first author, both from the Colorectal cancer research group at IDIBELL-ICO, has been recently published in the scientific journal Environmental International thanks to the support of the Spanish Association Against Cancer (AECC). Professionals from the ICO’s PADO (Data Analysis Program in Oncology) and researchers from CIBERESP have also participated.
Beyond exposure: the importance of susceptibility
The study was carried out within the framework of the MCC-Spain multicentre project, comparing data from 1037 colorectal cancer patients and 2100 healthy people. The aim was not to analyse the safety of water, which is already guaranteed by health controls. It was to understand if, in the face of the same relevant environmental exposure (as the prolonged exposure to chemicals present in the water we drink), the risk of developing colorectal cancer varies according to the genetics of everyone.
The results have allowed us to identify three specific genetic variants that seem to modulate the way in which exposure affects us, for years, to the by-products of water purification. In particular, the team of Dr. Víctor Moreno has observed that a variant related to the LRRC8B gene could play a relevant role in the biological response to trihalomethanes, increasing susceptibility to colorectal cancer and modulating the risk of developing tumors. “Our genetics can make us more or less sensitive to certain environmental exposures,” explains Dr. Víctor Moreno. “The combination of environmental factors and genetics is very complex and can be key to understanding the risk of developing cancer, in this case, colorectal. Therefore, the type of analysis we have carried out helps us to identify possible biological susceptibility factors”, he adds.
Trihalomethanes, a by-product of water disinfection
In the water purification process, chlorine treatment can generate by-products of water disinfection when reacting with organic matter. Trihalomethanes (THM), such as chloroform, are a common example, strictly controlled, but they may be more or less present in water supplies depending on the treatment that is carried out.
To evaluate exposure among the more than 3000 study participants, patients and healthy, the researchers estimated long-term exposure to THM according to water-registered levels for years (from 18 years to two years before the interview, resulting in a pre-2009 data collection; following 2009, the regulations on maximum levels of pollutants in water were strengthened). According to the results, a higher percentage of patients with colorectal cancer had lived in areas where the total amount of THM was higher than recommended.
In short, “the study we have carried out highlights the importance of studying our environment and our genes, simultaneously, to understand how certain daily environmental exposures interact and affect us”, continues Ferran Moratalla, first author of the study, member of the Oncobell program (IDIBELL) and the Oncology Data Analysis Program (ICO). Further research is needed to confirm the results obtained and explore the biological mechanisms involved in the link between exposure to THM, genetics and the risk of developing colorectal cancer.
The Bellvitge Biomedical Research Institute (IDIBELL) is a research center created in 2004 and specialized in cancer, neuroscience, translational medicine and regenerative medicine. It has a team of more than 1,500 professionals who, from 73 research groups, publish more than 1,400 scientific articles per year. IDIBELL is participated by the Bellvitge University Hospital and the Viladecans Hospital of the Catalan Institute of Health, the Catalan Institute of Oncology, the University of Barcelona and the City Council of L Hospitalet de Llobregat.
IDIBELL is a member of the Campus of International Excellence of the University of Barcelona HUBc and is part of the CERCA institution of the Generalitat de Catalunya. In 2009 it became one of the first five Spanish research centres accredited as a health research institute by the Carlos III Health Institute. In addition, it is part of the HR Excellence in Research program of the European Union and is a member of EATRIS and REGIC. Since 2018, IDIBELL is an Accredited Center of the AECC Scientific Foundation (FCAECC).