Background: A number of physiological cell signaling pathways can develop aberrations that lead to the complex breast cancer sickness. Objective: The effectiveness of Dendronephthya putteri ethanolic extract (DEE) against breast cancer caused by 7,
12‑dimethylbenz[a]anthracene (DMBA) in adult female albino rats was examined in this study. Materials and Methods: Adult female albino rats were divided into five groups of 10, each weighing between 160 and 200 g: group (1) normal rats serving as controls, group (2) normal rats receiving daily injections of DEE at a dose of 100 g/kg/day, group (3) animals with DMBA-induced breast cancer, group (4) animals modeled with breast cancer, and group (5) animals modeled for breast cancer receiving reference drug  5-Fluorouracil^® (5UR) (10 g/kg/weekly, ip) treatment for six weeks. Results: DEE injection considerably improved illnesses brought on by breast cancer, as seen by the sharp decline in serum cancer antigen 15.3 (CA15.3), carcinoembryonic antigen (CEA) and cancer antigen 19.9 (CA19.9) levels. Mammary malondialdehyde (MDA) and nitric oxide (NO), along with mammary superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), the activity and appropriateness of reduced glutathione (GSH) level, were all considerably increased. Other significant elevations were seen in tumor necrosis factor alpha (TNF-α), interleukin-1beta (IL-1β), alanine aminotransferase (ALT), aspartate aminotransferase (AST), urea, creatinine, cholesterol, and triglycerides. Conclusion: By enhancing immune function, lowering inflammation, and reversing oxidative stress, this study shows that DEE can prevent DMBA-induced breast cancer in rats.