CD8A and neoplasm: In contrast, in most cases of pMMR/MSS CRC, we revealed that the expression of cGAS-STING in tumor cells was maintained at a low level, at least partly due to epigenetic alterations such as histone methylation in the promoter region of STING, resulting in poor infiltration of CD8+ T cells and a worse prognosis in patients with pMMR/MSS CRC.