Introduction: The risk factors for breast cancer consist of intrinsic, extrinsic and hormonal factors.

Method: In the last ten years this meta-analysis taken literature based on full-text English journals published. This article aims to discuss the link between leptin levels and the incidence of breast cancer. The databases that we use in writing this article are Sage Pub, Pubmed and Google Schoolar. PICO (Patient, Index, Comparative, and Objective) analysis used in this study included patients with breast cancer, the index examined was the patient's leptin level, and comparisons were made on patients without breast cancer.

Result: When it comes to breast cancer, the hormone leptin has been connected to a number of various phases and processes, including the progression of the disease itself.Conclusion: Most of the studies obtained showed that patients with breast cancer had higher levels of leptin with more severe disease grade, metastases, and ER(+).

Keyword: Breast Cancer, Leptin, Obese, Menopaused