Department of Neurosurgery, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-Sen University Cancer Center, Guangzhou, China.|School of Mathematics, Sun Yat-Sen University, Guangzhou, China.|School of Life Science, Sun Yat-Sen University, Guangzhou, China.|School of Mathematics, Sun Yat-Sen University, Guangzhou, China.|School of Mathematics, Sun Yat-Sen University, Guangzhou, China.|School of Mathematics, Sun Yat-Sen University, Guangzhou, China.