The significant co‐expression of PTX3 and macrophages/microglia markers, CD68 and CD163, based on multiplex immunofluorescence staining in tumor tissues of GBM, astrocytoma, HNSCC, ureteral urothelial carcinoma, THCA, urothelial carcinoma of the renal pelvis, BLCA, CESC, UCEC, squamous cell carcinoma of the penis, ovarian papillary cystadenocarcinoma, serous ovarian adenocarcinoma, TGCT, PRAD, and some corresponding normal tissues proved the potential role of PTX3 in the infiltration of macrophages/microglia. This evidence concerns the gene CD163 and head and neck squamous cell carcinoma.