(A) Fam20C expression is significantly negatively related to tumor purity has significant positive correlations with infiltrating levels of CD8⁺ T cells, CD4⁺ T cells, macrophages, neutrophils, and dendritic cells in BLCA. Fam20C expression shows a very weak correlation with B-cells infiltration level in BLCA. (B) Fam20C expression has a week correlation with tumor purity and is significantly positively correlated with infiltrating levels of B cells, CD4⁺ T cells, macrophages, neutrophils, and dendritic cells in LGG, other than CD8⁺ T cells. (C) Fam20C expression is positively related to tumor purity and CD4⁺ T cells, and has a negatively weak relation with CD8⁺ T cells infiltration level in LIHC. Further, there is no relation with infiltrating levels of B cells, macrophages, neutrophils, and dendritic cells. (D) Fam20C expression is negatively related to tumor purity and has significant positive correlations with infiltrating levels of CD4⁺ T cells, macrophages, neutrophils, and dendritic cells in STAD but no significant correlation with infiltrating level of B cells and CD8⁺ T cells.