FBXO6(F-box only protein 6 ) is also named as FBG2, FBS2, FBX6 and belongs to the F-box protein family. It can regulate Chk1 ubiquitination and degradation in both normally cycling cells and during replication stress. This protein is mainly detected in the cytoplasm in both cultured cells and in tumor tissues. Its expression is a predictive biomarker of tumor responsiveness to the important anticancer drugs.(PMID:19716789). FBXO6 can inhibit the anaphase promoting complex (cyclosome APC) and prevent mitotic exit in cytostatic factor (CSF) arrested eggs as a mitotic regulator.