Osteoprotegerin as a Potential Biomarker for Breast Cancer: A Study of Its Relationship with Bone Health, vitamin D, and Calcium Levels

Breast cancer continues to be a significant global health issue and is associated with various biological indicators, including osteoprotegerin (OPG), a glycoprotein involved in bone metabolism, tumor progression, and immunological modulation. This study examined the potential of OPG as a biomarker for breast cancer and its correlation with bone health, vitamin D levels, and calcium concentrations. To quantify serum OPG levels in breast cancer patients and assess its viability as a diagnostic biomarker. In addition, to evaluate vitamin D levels due to their established correlation with an increased cancer risk in cases of deficiency. The study also examined parathyroid hormone (PTH) and calcium levels in breast cancer patients. Blood samples were obtained from female volunteers at the Oncology Teaching Hospital, Medical City, Baghdad, Iraq (September 2023 - February 2024). The study comprised three cohorts: healthy controls (G1, n=40), newly diagnosed breast cancer patients (G2, n=45), and patients undergoing chemotherapy (G3, n=45). Serum concentrations of OPG, vitamin D, PTH, and calcium were quantified using ELISA methodologies. No statistically significant variations in OPG levels were observed between the control and patient groups, indicating minimal bone resorption during the early stages of breast cancer. Vitamin D levels were markedly reduced in G2 compared with the control group, while G3 showed a modest increase in vitamin D levels attributable to supplementation. Increased PTH levels were observed in breast cancer patients, supporting prior research linking elevated PTH with increased cancer risk. No notable differences were found in serum calcium levels among the groups. Vitamin D and PTH levels are crucial in early-stage breast cancer development, underscoring the need for monitoring these factors and questioning the diagnostic efficacy of OPG alone.