TFF2 and cryptorchidism: Moreover, the abnormal expression of some proteins in the process of testicular descent is also one of the important causes of cryptorchidism, including INSL-3, NSE, SP, NFH, and DβH, which are closely related to the formation of cryptorchidism (Krausz et al., 2000; Yuan et al., 2021; Yuan et al., 2022).