A groundbreaking study recently published in BMC Cancer sheds new light on the complex interplay between metabolic markers, genetic predisposition, and the risk of developing breast cancer in postmenopausal women. This extensive research conducted using the UK Biobank cohort delves into the association of triglyceride-glucose (TyG) related indicators—a novel cluster of simple surrogate markers reflecting insulin resistance—and genetic risk scores, uncovering critical insights into breast cancer incidence after menopause.
The study explores five specific TyG-related indicators: TyG itself, TyG combined with waist circumference (TyG-WC), waist-to-height ratio (TyG-WHtR), waist-to-hip ratio (TyG-WHR), and body mass index (TyG-BMI). These composite indicators serve as accessible and efficient markers for insulin resistance, a metabolic state increasingly implicated in carcinogenesis. The research aimed to evaluate whether these indicators, either alone or in conjunction with genetic susceptibility estimated through polygenic risk scores (PRS), could help refine breast cancer risk prediction models.
Leveraging data from an impressive cohort of over 83,000 postmenopausal women followed for an average of nearly 14 years, the investigators identified 3,561 incident cases of breast cancer. Such a robust sample size and longitudinal follow-up provide considerable statistical power to detect subtle but clinically significant associations. Using sophisticated Cox proportional hazards regression models, adjusted for potential confounders, the study elucidates the nuanced relationship between metabolic markers and breast cancer risk.
What emerges is a clear pattern: elevated levels of TyG-related indicators independently correlate with a modest but statistically meaningful increase in breast cancer risk. For instance, women in the highest quartile of TyG-WC exhibited a 35% greater risk compared to those in the lowest quartile. Importantly, these associations held even after controlling for traditional risk factors, underscoring the potential of TyG-related markers as valuable tools in risk stratification.
The study also highlights the nature of the relationship between these markers and breast cancer risk. Notably, TyG-WC demonstrated a nonlinear association, suggesting that risk escalates disproportionately beyond certain metabolic thresholds. Such findings support a more nuanced view of how metabolic dysfunction contributes to oncogenesis, going beyond simple linear risk increments.
Simultaneously, the role of genetics was elucidated through the categorization of participants into polygenic risk strata. Women with high genetic susceptibility exhibited elevated breast cancer risk independently, as expected. However, the landmark finding lies in the additive effect observed when combining high genetic risk with high levels of TyG-related indicators. These women faced a staggering 4- to 5-fold increase in breast cancer risk relative to the reference group with low risk in both domains, illustrating the profound interplay between inherited and metabolic risks.
The mechanism linking these metabolic indices to breast carcinogenesis was further interrogated through mediation analysis. The study found that sex hormone-binding globulin (SHBG), C-reactive protein (CRP), and testosterone significantly mediated the association between TyG-related indicators and breast cancer. This indicates that complex pathways involving hormone regulation and systemic inflammation may partly explain how insulin resistance accelerates breast tumor development.
Specifically, SHBG is known for regulating bioavailable sex hormones, which are critical players in hormone-driven breast cancer subtypes. Elevated CRP levels reflect a chronic inflammatory state, increasingly recognized as a cancer-promoting milieu. Meanwhile, testosterone, modulated via insulin resistance pathways, influences estrogen dynamics and cellular proliferation in mammary tissue, potentially exacerbating tumor development.
Another key insight from this investigation is the absence of multiplicative interaction between genetic risk and TyG indicators. Rather than synergistically amplifying risk multiplicatively, the combined effect is additive, which importantly informs risk modeling strategies and clinical translation. This suggests that while both domains independently increase risk, their combined influence follows an accumulative pattern.
These findings have significant ramifications for breast cancer prevention and early detection strategies. Traditional risk models primarily focus on inherited genetic risk and reproductive history; incorporating metabolic indicators of insulin resistance could enhance predictive accuracy. Given the widespread availability and cost-effectiveness of metabolic measurements compared to genetic testing, TyG-related indicators could serve as accessible biomarkers for identifying women at heightened risk who might benefit from tailored interventions.
Furthermore, the study underscores the public health implications of metabolic health management. The modifiable nature of insulin resistance through lifestyle interventions such as diet, exercise, and pharmacotherapy contrasts with the immutable nature of genetics. Thus, targeting metabolic dysfunction may represent a practical avenue to mitigate breast cancer risk, especially in genetically predisposed populations.
Importantly, the UK Biobank resource, which underpins this research, offers unparalleled depth and breadth of phenotypic and genotypic data, enabling rigorous assessment of complex disease etiology. Such large-scale epidemiological investigations pave the way toward precision medicine frameworks that integrate multifactorial risk components.
Despite the compelling findings, the authors acknowledge limitations inherent to observational cohort studies, including residual confounding and potential measurement variability in metabolic indices. Nonetheless, the consistency and biological plausibility of the results provide confidence in their relevance.
Looking forward, further research is warranted to explore whether integrating TyG-related markers into clinical risk models improves breast cancer screening efficiency or informs preventive pharmacological approaches. Additionally, experimental studies probing the underlying molecular crosstalk between metabolic and genetic risk pathways may yield novel therapeutic targets.
In sum, this pioneering study presents a paradigm shift in understanding postmenopausal breast cancer risk by linking metabolic markers of insulin resistance with genetic susceptibility. The demonstrated additive interaction reinforces the necessity to consider both inherited and environmental-metabolic factors in comprehensive risk assessment. As breast cancer remains a leading cause of morbidity worldwide, insights from this research may accelerate progress toward more personalized and effective prevention strategies.
This work exemplifies the power of integrating multi-dimensional biological data to unravel complex disease mechanisms. It opens new vistas for leveraging routine clinical biomarkers alongside genetic screening in combating breast cancer, potentially transforming public health approaches for an aging female population burdened by both metabolic syndrome and cancer risk.
Subject of Research: The study investigates the association between triglyceride-glucose related indicators (surrogate markers of insulin resistance), genetic risk assessed via polygenic risk scores, and incident postmenopausal breast cancer.
Article Title: Association between triglyceride-glucose related indicators, genetic risk, and incident breast cancer among postmenopausal women in UK Biobank.
Article References:
Li, Z., Zhao, Z., Zhang, T. et al. Association between triglyceride-glucose related indicators, genetic risk, and incident breast cancer among postmenopausal women in UK Biobank. BMC Cancer 25, 781 (2025). https://doi.org/10.1186/s12885-025-13970-y
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