The purpose of this study was to characterize the densities of CD3+, CD8+, CD4+ and FOXP3+ T cells in small bowel neuroendocrine tumors (SB-NETs), SB-NET lymph node metastases and gastric neuroendocrine tumors (G-NETs) to assess the prognostic role of immune cell infiltrates in SB-NETs. This evidence concerns the gene CD4 and small intestine neuroendocrine neoplasm.