The invention provides a PD-L2 inhibitor, a preparation method and application and an anti-
cancer composition, the PD-L2 inhibitor has the following
structural formula: # imgabs0 #, in which R group is one of
hydrogen,
deuterium, methyl, methoxyl, trifluoromethoxyl,
halogen, amino, carbamido, sulfamido and
sulfonyl or a combination of the above
substituent groups, and R group is one of
hydrogen,
deuterium, methyl, methoxyl, trifluoromethoxyl,
halogen, amino, carbamido, sulfamido and
sulfonyl; x, Y and Z are respectively carbon atoms,
nitrogen atoms and
sulfur atoms, and the positions of the carbon atoms, the
nitrogen atoms and the
sulfur atoms can be mutually replaced; the PD-L2 inhibitor can inhibit expression and
glycosylation of PD-L2 on the surfaces of
tumor cells, so that the recognizability and aggressiveness of an
immune system to the
tumor cells are improved, and the
immune defense capability of a
human body is improved.