This book about a common disease among women in third world. This work explain the role of insulin level as a risk factor for breast cancer and it is role for indicator breast cancer development. In addition,after therapy many factors that increase the probability of breast cancer recurrence like hypoxia, body mass index,weight change and life style as well as the prognostic and predictive factors such as hormone receptors. All these factors have potential effect on insulin levels and lead to increase the concentration of insulin in blood circulation that cause hyperinsuleneamia ,which considered a major method for indicator insulin resistance. This book focused mainly to evaluate the serum insulin levels in breast cancer women pre and post chemotherapy to a chive the different between the concentration of insulin at diagnosis and after therapy.Patients were observed prospectively for two years dependent on the insulin levels associated with some factors include body mass index,menopause status,estrogen receptor,progesterone receptor and HER2.Also the newly diagnosis breast cancer patients were compared to health women as control.