Background: Breast cancer (BC) is the most widespread cancer among women worldwide. Its incidence and mortality rates have risen in the previous three decades as a result of changes in risk factor profiles, improved cancer registry, and cancer detection. Objective: The study's goals were to establish if Ki-67 could be used as a potential marker in serum of cancer disease patients as well as their interaction with vascular endothelial growth factor (VEGF) and ES in various stages of breast cancer to assess their function in the progression of BC. Materials and Methods: The levels of Ki-67, VEGF and endostatin (ES) in serum were assessed by commercial enzyme linked immunosorbent assay (ELISA) kits in 60 women diagnosed with breast cancer (age range 33–80 yrs.) and 30 agematched healthy controls. Two groups of breast cancer patients: groups 1 consisted of stage II (Low level) and groups 2 consisted of patients in stage III and IV (High level). Results: The results showed a significant increase of Ki-67 and VEGF in BC patients as related to healthy control with increases in patients in advanced stage. The data revealed that the level of ES was much lower in patients with low-stage (stage II) compared to the group of control, but it was significantly higher in women with advanced-stage of BC. Conclusions: The Ki-67, VEGF, and ES levels in the serum of studied groups may be a good marker in the progression of BC.
