In summary, our data support that CXXC5 acts as a potential suppressor of TSC1 and indicates that the vitamin-CXXC5/CRL4B/NuRD-TSC1/mTOR-PD-L1 axis is associated with breast carcinogenesis, providing insights into the function of CXXC5 in tumorigenesis and supporting the use of CXXC5 as a diagnostic and therapeutic target for breast cancer in the future. Here, CD274 is linked to breast carcinoma.