LKB1, A New Biomarker in Breast Cancer

Abstract

Breast cancer is the most common cancer in women worldwide. Estrogen signaling pathways have been identified as efficient targets of breast cancer therapy, given their key role in promoting breast tumor growth. Agents blocking estrogen-mediated pathways are routinely used in clinical applications in patients displaying estrogen-sensitive breast cancer subtypes; however intrinsic or acquired resistance to treatment often occurs or develops, thus limiting their efficacy. This limitation has highlighted an imperative need to identify new predictive biomarkers. Recent findings have highlighted a role for the Liver Kinase B1 (LKB1) in breast cancer tumorigenesis. LKB1 is a serine/threonine kinase mutated in Peutz-Jeghers syndrome (PJS), implicated in many cellular processes including energy metabolism, cell polarization and cell cycle arrest and has also been shown to play an essential role as a tumor suppressor gene by negatively regulating the mTOR pathway. This review provides an overview of previous findings and ongoing research on LKB1, and substantiates the use of this kinase as a potential prognostic and predictive biomarker of breast cancer.