(A) Pearson’s correlation between commonly identified proteins in both comparative proteomic analyses analyzed using log₂ ratio of abundance changes. (B) Heatmap clustering analysis of quantified proteins with significant abundance ratios (P < 0.05) in both comparative proteomes. (C) Scatterplots demonstrating the relationship between ratio weights and abundance ratios for each identified protein in the proteomic analysis. The color of protein dots represents the P value for corresponding abundance ratios. (D) ICAM1 expression in OECM-1 cells cocultured with THP-1–derived macrophages and PBMC M1-like or M2-like macrophages. (E) Spearman’s monotonic correlation between ICAM1 and CD163 expression in HNSCC analyzed using the TCGA RNA-Seq database on the GEPIA server. TPM, transcripts per million. ICAM1 in FaDu, OECM-1, and CE146 cells induced by (F) CM or (G) 20% CM at different periods. (H) Spheroid formation in FaDu and SAS cells in the presence or absence of 20% CM for 12 days (n = 3). (I) Number of spheroids formed in ICAM1-KD and control CE146T cells in the presence or absence of 20% CM for 12 days (n = 3). The effect of ICAM1 inhibition by shRNA was validated (right). Effects of (J) 20% CM treatment and (K) ICAM1-KD on CD44 expression in FaDu and OECM-1 cells. (L) mRNA levels of ZEB1 and ZEB2 in OECM-1 cells treated with CM determined by quantitative PCR and normalized to untreated control (set as 1, dashed line). GAPDH, β-actin, and 18S rRNA mRNA were internal controls for gene expression. (M) Levels of EMT-related proteins in OECM-1 cells induced by CM. β-actin, loading control. (N) Transwell migration and (O) invasion assays performed using OECM-1 cells in the presence or absence of 10% CM. Signal quantification with crystal violet extract measured by colorimetric analysis at 570 nm (n = 3). Means ± SD. Two-tailed unpaired Student’s t test (H, I, N, and O). **, P < 0.01.