Meat Consumption Linked to Genetic Bowel Cancer Risk

Researchers, aware of the association between consuming red and processed meat and colorectal cancer rates but lacking comprehension of its biological mechanisms, have recently pinpointed two genetic indicators that might elucidate this connection. Grasping the disease’s progression and the genes involved could aid in devising more effective prevention measures.

Bowel cancer, also referred to as colorectal cancer, ranks as the third most prevalent cancer and the second primary cause of cancer-related mortality globally. Moreover, its incidence among younger individuals is increasing, as reported by the American Cancer Society (ACS), with approximately 20% of diagnoses in 2019 occurring in patients under 55 years old – a figure nearly twice the rate recorded in 1995.

Unveiling Genetic Links Between Cancer Risk and Red Meat Consumption

Researchers at the Keck School of Medicine, USC, have recently uncovered two genes associated with cancer risk, particularly tied to red and processed meat consumption. Lead author Mariana Stern noted, “These findings imply that a subgroup of the population may face an elevated risk of colorectal cancer with increased intake of red or processed meat.”

The study involved analyzing data from 29,842 colorectal cancer cases and 39,635 controls across 27 studies. Participants were categorized based on their consumption of red or processed meat, with those consuming the highest amounts facing a 30% and 40% higher risk of colorectal cancer, respectively. The study did not consider genetic variability, which could potentially increase the risk for certain individuals.

The researchers collected DNA data from each participant, focusing on over seven million gene variants. They conducted a comprehensive analysis to examine the interaction between red meat consumption and cancer risk at a genome-wide level. Researchers assessed single nucleotide polymorphisms (SNPs) as biological markers to identify genes associated with disease.

Genetic Variants and Colorectal Cancer Risk in Relation to Red Meat Consumption

The researchers analyzed participants’ single nucleotide polymorphisms (SNPs) to assess whether specific gene variants influenced colorectal cancer risk in those with higher red meat consumption. They identified two SNPs associated with altered cancer risk: one near the HAS2 gene on chromosome 8 and another on chromosome 18, part of the SMAD7 gene.

The HAS2 gene is implicated in cell protein modification and previously linked to colorectal cancer, but not red meat consumption. Individuals with a common variant of this gene, found in 66% of the population, faced a 38% higher colorectal cancer risk with increased red meat intake. Conversely, those with a rarer variant did not experience heightened cancer risk despite elevated red meat consumption.

SMAD7 regulates hepcidin, a protein involved in iron metabolism. Given that red and processed meats contain heme iron, readily absorbed by the body, the researchers suggested that different SMAD7 variants might affect iron processing, thus influencing cancer risk.

Lead author Mariana Stern stated, “Dysregulated hepcidin can lead to increased iron absorption and iron overload within cells.”

Colorectal Cancer Risk in Relation to SMAD7 Gene Variants and Red Meat Intake

Individuals with two copies of the most common SMAD7 gene variant, found in roughly 74% of the population, had an 18% higher colorectal cancer risk with elevated red meat intake. However, those with one copy of the common variant or two copies of a less common variant faced significantly higher cancer risks: 35% and 46%, respectively.

Co-author Joel Sanchez Mendez remarked, “These findings suggest varying colorectal cancer risks among individuals consuming red meat due to different genetic variants and offer insight into potential disease development mechanisms.”

The study’s findings do not definitively establish a causal relationship between these genetic variants and the consumption of red and processed meat.

“This offers significant food for thought,” Stern emphasized. “We conduct these gene-environment interaction studies when there’s a clear connection between an environmental factor and a disease, but the intermediate mechanisms remain unclear.”

The researchers aim to conduct experimental studies to further solidify evidence regarding the impact of dysregulated iron metabolism on colorectal cancer development.

Read the original article on: New Atlas

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