(A) CD14⁺ cells were purified from tumor tissues from 41 patients with HCC. Correlations between the mRNA levels of GLUT1 and CA12 in these cells were analyzed. (B) Frozen sections of HCC samples were stained with an anti-human CD68 antibody (red), an anti-human CA12 antibody (green), an anti-human GLUT1 antibody (white), and DAPI (blue). The colocalization of cell signals was analyzed by confocal microscopy. Scale bar: 50 μm. n = 5. (C–I) CD14⁺ and CD14^– leukocytes were purified from the peripheral blood of healthy donors. (C and D) CD14⁺ cells were left untreated (Med) or treated with supernatants from HepG2 cells (TSN) for 24 hours. Levels of CA12 expression were determined by qPCR (C) (n = 10) and confocal microscopy (D) (n = 5; CA12: green; DAPI: blue). Scale bar: 50 μm. (E and F) CD14⁺ cells were left untreated or treated with HepG2 TSN for the indicated times. Levels of CA12 expression were determined by immunoblotting (E) (n = 5), and levels of lactate production were measured with a lactate assay kit (F) (n = 4). (G) CD14⁺ cells were treated with HepG2 TSN for 24 hours, and correlations between mRNA levels of GLUT1 and CA12 in these cells were analyzed (n = 22). (H) CD14⁺ and CD14^– leukocytes were left untreated or treated with HepG2 TSN for 24 hours, and levels of CA12 expression were determined by immunoblotting (n = 3). (I) CD14⁺ cells were left untreated or treated with TSN from different cell lines for 48 hours, and levels of CA12 expression in the cells were determined by immunoblotting (n = 3). Results shown in B–D and F are represented as mean ± SEM. P values were obtained by Pearson’s correlation and linear regression analysis (A and G), 2-way ANOVA (B), or 2-tailed Student’s t test (C, D, and F). *P < 0.05; ***P < 0.001.