SEMA6A and neoplasm: Several semaphorins including Sema3a, Sema3f, Sema3g and Sema6a have been reported to exert tumor growth-inhibiting activities while several others such as Sema4d and Sema6d have been associated with tumor-promoting functions in various cancer types (Law and Lee, 2012; Angelucci et al., 2019).