CD274 and triple-negative breast carcinoma: The integrated membrane scaffold protein SIGMA I stabilizes and enhances PD-L1 in tumor cells by preventing its autophagic degradation to a large extent (74), and in triple-negative breast cancer and androgen-independent prostate cancer cells expressing SIGMA I, the interaction between SIGMA I and glycosylated PD-L1 results in the inhibition of PD-L1 autophagic degradation.