NT5E and neoplasm: It was reported that Osa may contribute to restricting engrailed (en) expression in embryo [63], indicating that Osa is a repressor of en. Meanwhile, ectopic expression of en in ECs leads to ectopic BMP signaling, resulting in an expanded GSC-like cell tumor phenotype [22], and En regulates dpp2.0-lacZ reporter activity in CpCs [62].