Evaluating IGF1 and IGF1-R Levels as Risk-Related Indicators and Early Detection Tools in Estrogen Receptor–Positive Breast Cancer

Breast cancer (BC) remains one of the most common malignancies in women, with its development strongly influenced by hormonal and growth factor signaling. The insulin-like growth factor 1 (IGF1) and its receptor (IGF1-R) are increasingly recognized as key contributors to breast carcinogenesis, particularly in relation to estrogen receptor (ER) status. This study aimed to evaluate circulating IGF1 and IGF1-R levels among Iraqi women with BC and to explore their diagnostic and biological relevance. A total of 90 participants were enrolled, including 65 patients with histologically confirmed BC (41 ER-positive and 24 ER-negative) and 25 healthy controls. Serum concentrations of IGF1 and IGF1-R were measured using ELISA, and statistical analyses were performed with ANOVA, correlation testing, and receiver operating characteristic (ROC) curve assessment. The results demonstrated that both IGF1 and IGF1-R levels were significantly elevated in ER-positive BC patients compared to ER-negative BC patients and healthy controls, whereas no significant differences were observed between ER-negative cases and controls. ROC analysis confirmed the discriminatory potential of these biomarkers, with IGF1 achieving an AUC of 0.8679 when distinguishing ER-positive from ER-negative tumors, while IGF1-R exhibited high specificity (97.44%) at optimal cut-off values. Moreover, a moderate positive correlation was observed between IGF1 and IGF1-R in ER-positive patients, suggesting coordinated regulation within this subgroup. These findings highlight the subtype-specific role of the IGF axis in BC and support the potential clinical utility of IGF1 and IGF1-R as diagnostic indicators and risk-related factors for ER-positive BC. Elevated IGF1 and IGF1-R levels, were observed even in stage I cases, indicating their potential as early biomarkers that could complement mammography in the detection of ER-positive BC.