In tumor tissues, FAM111B-positive cells (p = 0.0068), CD8+ T cells, CD4+ T cells, Tregs, CD4+ Teff cells (all p < 0.0001), M2 macrophages (p = 0.0002), and DCs (p = 0.0004) were present at higher levels in serous carcinoma samples relative to mucinous carcinoma samples. Here, CD8A is linked to mucinous adenocarcinoma.