Breast cancer is the most common malignancy affecting women's health, with an increasing incidence worldwide. This study aimed to measure the intracellular concentration of the hypoxia-inducible factor 1 a (HIF-1a), tumor suppression protein p53, and estradiol (E2) in tumor tissues of adult females with breast cancer and their relation to tumor grade, tumor size, and lymph node metastases (LNM). The study was conducted on 65 adult female participants with breast mass admitted to the operating theater in Al-Hussein Teaching Hospital and Al-Habboby Teaching Hospital in Nasiriyah, Iraq, from January to November 2021. Fresh breast tumor tissues were collated and homogenized for intracellular biochemical analysis using the enzyme-linked immunosorbent assay method. In total, 44 (58%) out of 65 patients, in the age range of 18-42 years and the mean±SD age of 32.55±6.40 years, had fibroadenomas, and other 21 (42%) cases, in the age range of 32-80 years and the mean±SD age of 56±14.4 years had invasive ductal carcinoma (IDC) breast cancer. Intracellular levels of HIF-1a, p53, and E2 were elevated significantly (P<0.001) in IDC cases compared to the benign group. The most malignant tumors of IDC cases were in grade III and sizes T2 and T3. The tissue concentrations of HIF-1a, P53, and E2 were significantly elevated in patients with tumor stage T3 compared to T2 and T1. A significant elevation was found in the levels of HIF-1a, p53, and E2 in the positive LNM subgroup compared to the negative LNM group. Based on the obtained results, the prognostic value of the intracellular HIF-1a is considered to be a useful prognostic factor in Iraqi women with ICD and the combination of a HIF-1a protein with the nonfunctional p53 and E2 tends to indicate the proliferation, invasiveness, and metastases of the breast tumors. [ABSTRACT FROM AUTHOR]