Diet, hormones, and breast cancer: biomarker-guided assessment of risk and prognosis.

Despite growing recognition that nutritional factors modulate breast cancer risk and prognosis through endocrine and metabolic pathways, existing reviews have predominantly focused on individual nutrients or single hormonal axes, lacking an integrated framework that systematically connects nutritional biomarkers across biological scales to clinical prediction models. Furthermore, the translational gap between biomarker discovery and clinical implementation-compounded by pre-analytical variability, population heterogeneity, and the absence of standardized testing protocols-remains inadequately addressed in the current literature. This review synthesizes contemporary evidence on nutritional biomarkers and their interactions with endocrine-related mechanisms in breast cancer, with a specific focus on risk assessment and prognosis prediction. We systematically integrate four core endocrine-metabolic axes (estrogen signaling, insulin/IGF-1 pathway, adipokine homeostasis, and inflammatory-oxidative stress) with four functional classes of nutritional biomarkers (recovery, concentration, replacement, and predictive), delineating their hierarchical relationships and complementary clinical roles. We further examine subtype-specific metabolomic signatures associated with differential prognosis across triple-negative, luminal-like, and HER2-enriched breast cancer, and evaluate the clinical utility of integrating multi-dimensional biomarkers into prognostic prediction models including nomograms. Our analysis reveals that while circulating vitamins, fatty acid profiles, and inflammatory biomarkers demonstrate consistent associations with breast cancer risk, their prognostic value varies substantially by molecular subtype and menopausal status; composite metabolomic signatures outperform single biomarkers in prognostic discrimination, yet most evidence derives from retrospective single-center cohorts with limited external validation. We conclude that biomarker-guided precision nutrition holds substantial promise for advancing personalized breast cancer prevention and management, but critical barriers-including non-standardized assay protocols, underrepresentation of non-Western populations, and a paucity of prospective intervention trials-must be addressed before widespread clinical translation.