The expression of the MAN2B2 homolog can serve as a good marker for the late stages of type A spermatogonia and may have an important role to play in the early step of spermatogenesis in mice. Two structurally-related members of the lysosomal mannosidase family, the broad substrate specificity enzyme human lysosomal alpha-mannosidase (hLM, MAN2B1) and the human core alpha-1, 6-specific mannosidase (hEpman, MAN2B2) act in a complementary fashion on different glycosidic linkages, to effect glycan degradation in the lysosome. At least two kinds of alpha-D-mannosidase (lysosomal type enzyme and 135 kDa alpha-D-mannosidase (MAN2B2)) were contained in the porcine epididymal fluid. The activity of the lysosomal type enzyme is much higher than MAN2B2 at the physiological pH. circRNA MAN2B2 (circMAN2B2) acted as an Onco-miRNA in hepatocellular carcinoma (HCC) by sponging miRNA-217 to promote MAPK1 expression.