The results of the present study suggest the clinical significance of examining tumour PD-L1 expression and using anti-PD-1 or anti-PD-L1 antibodies as adjuvant therapy for patients with solid-predominant adenocarcinoma, even at p-stage I. We could not find any reports describing the relationship between CD155 expression and adenocarcinoma subtype when searching MEDLINE. Here, PDCD1 is linked to adenocarcinoma.