Figure 6. Schematic diagram of HO-1 regulating CD163 expression and tumor-associated macrophage (TAM) polarization in the progression of nasopharyngeal carcinoma. The overexpression of HO-1 could promote CD163 expression, and drive TAM polarization toward M2 phenotype. Finally, M2 TAMs related immune escape promotes the progression of nasopharyngeal carcinoma.