GCKR and breast carcinoma: In most cases, GCKR expression was significantly higher in normal tissues compared to tumor tissues (e.g., breast cancer [BRCA], cholangiocarcinoma [CHOL], HNSC, and KICH), while only a few cancers such as kidney renal papillary cell carcinoma (KIRP), lung adenocarcinoma (LUAD), and THCA showed elevated GCKR expression in tumor tissues (Figure 1a and Supporting Information 1: Figure S1A).