CD8A and neoplasm: On the other hand, they observed that PDO-retained tumor-infiltrating lymphocytes (CD3+) were integrally embedded in close proximity to the tumor epithelium, macrophages, cytotoxic T cells (CD8+), helper T cells (CD4+), natural killer (NK) cells, and natural killer T (NKT) cells, which they were able to support using IL-2 supplementation until 60 days of culture.