In our study, the expression of PD-1/PD-L1 in FLUGC was not prominent (PD-1 < 1–5%; PD-L1: TPS = 1–4%, CPS = 3–8), indicating the inactive immune response of fibromatosis-like undifferentiated gastric carcinoma. The gene discussed is PDCD1; the disease is fibromatosis.