Beyond the common increased IL6 and sB7.2 expression levels displayed by both tumor entities compared to HVs (Fig. 2), pheochromocytomas showed heightened MCP1, sPD-L1 and sCD25 levels, while paragangliomas exhibited reduced sPD-L2 expression with increased levels of sLAG3 and Galectin-9. This evidence concerns the gene CCL2 and hereditary pheochromocytoma-paraganglioma.