Abstract: More than 1.3 million women worldwide are diagnosed with breast cancer annually.This disease is the second most common form of cancer, after lung cancer.Heat shock protein-27(HSP27) is a ubiquitous small heat shock protein expressed in eukaryotic cells.HSP27 is an ATP-independent molecular chaperone that allows the cells to survive in otherwise lethal conditions caused by a wide variety of physiological and environmental factors.Recent studies have shown that a sustained high-level of HSP27 expression exists in breast cancer cells.This expression is considered to be closely related to breast cancer development, prognosis, and resistance to chemotherapy.Breast cancer genesis, proliferation, invasion, and metastasis are extremely complex and multi-step dynamic processes.In-depth studies on HSP27 in breast cancer genesis and development mechanism will provide new information for the prevention and treatment of breast cancer.