He received his PhD in Microbiology from Medical College of Wisconsin in 1995 and his Bachelor of Science degree in biochemistry from Fudan University, Shanghai, China in 1989. Dr. Xu received his postdoctoral training at Vanderbilt University School of Medicine in Biochemistry. He was recruited to join the Dermatology Department in 1999. Dr. Xu's current interest includes ultraviolet (UV) light irradiation-induced redox signaling and regulation of growth factor receptor tyrosine kinase functions by protein tyrosine phosphatases in human skin and in head and neck cancer.