LAUSR

53Background: The prognostic impact of tumor-infiltrating T lymphocytes has been evaluated in periampullary carcinoma, but previous studies have not taken into consideration the different morphological subtypes of cancers derived from the periampullary region. Herein, we investigated the prognostic impact and distribution of tumor-infiltrating CD3+, CD8+, FoxP3+ T lymphocytes as well as IL-17+cells in periampullary adenocarcinoma, with particular reference to morpohological subtyoe. Methods: Counts of CD3+, CD8+, FoxP3+ T lymphocytes, and IL-17+cells were assessed using immunohistochemistry on tissue microarrays with tumors from a consecutive retrospective cohort of 175 patients with resected periampullary adenocarcinoma; 110 of pancreatobiliary type (PB-type) and 65 of I intestinal type (I-type). Results: Distribution of all evaluated immune cells differed significantly between PB- and I-type tumors. In I-type tumors, the ratios of IL-17+/FoxP3+ and IL-17+/CD3+ were independent factors of poor prognosis....