CD274 and breast cancer: To evaluate the clinical roles of the TMUB1-mediated regulation of PD-L1, we assessed the levels of TMUB1 and PD-L1 in the tissue samples from the tissue microarrays integrated from individuals with breast cancer, which were obtained from the Cancer Center of Sun Yat-sen University (Supplementary Table 3), and from individuals with gastric cancer, which were obtained from the Second Affiliated Hospital of Zhejiang University (Supplementary Table 4).