For instance, mouse 4 T1 mammary tumor cells expressing wild-type PD-L1 grew faster than did 4 T1 cells expressing PD-L1 4NQ mutant in immunocompetent BALB/c mice, but no significant differences were observed in severe combined immunodeficient (SCID) mice, supporting the notion that glycosylation of PD-L1 is important for its immunosuppressive function in vivo and that the differential tumorigenicity is attributed to immune surveillance [36]. Here, CD274 is linked to breast cancer.