PECAM1 and neoplasm: Furthermore, to investigate the clinical relevance of STING palmitoylation and tumor immunity, we examined the level of STING palmitoylation by a modified acyl-biotinyl exchange (ABE) assay integrated with proximity ligation assay (PLA), and the expression of CD31, STING, and CD8+ T cell expression by multiplex immunofluorescence staining in tumor tissue from patients with melanoma.