ENPP1/cGAS (EG) and FAP Expression Profiles in Solid Tumors: An Immunohistochemical Study in a Vietnamese Cohort

This Vietnam-based observational study examines ecto-nucleotide pyrophosphatase/phosphodiesterase 1/cyclic GMP-AMP synthase (ENPP1/cGAS) protein and stromal fibroblast activation protein (FAP) expression in multiple solid tumor samples using immunohistochemistry (IHC). The study involves no investigational treatments or participant-facing procedures. Tumor samples used in this study consist exclusively of archived formalin-fixed paraffin- embedded (FFPE) tumor samples that were collected as part of routine clinical diagnosis or treatment and for which all required procedures for standard clinical care have been completed. Only archived tumor samples obtained from routine clinical care will be included in this study. No additional biopsy, surgical resection, or specimen collection will be performed for research purposes, and no sample will be diverted prior to completion of clinical requirements. All included archived tumor samples will undergo ENPP1, cGAS, and FAP IHC analysis according to the procedures specified in the Laboratory Manual.