The immune system component of OMS was investigated in a pancreatic ductal adenocarcinoma culture slice model were the authors observed the presence of CD8+ T cells (CD3+ CD8+), Tregs (CD3+, FoxP3+), and macrophages (CD68+, CD163+, HLA-DR+) (56). This evidence concerns the gene CD8A and pancreatic ductal adenocarcinoma.