Indolamine-2,3-dioxygenase (IDO) is an intracellular enzyme that catalyzes amino acid tryptophan to L-kynurenine. When the results are accumulated, IDO immunohistochemistry will be a useful tool to diagnose lymphomas and to predict their prognosis. strong class=”kwd-title” Keywords: Indolamine-2,3-dioxygenase (IDO); lymphoma; immunohistochemistry (IHC) 1. Introduction Tumors express the antigens that induce the host immune response. Progression of tumors requires avoidance of host immune surveillance [1,2]. Recent studies have shown that tryptophan catabolism is usually one means of avoiding immune surveillance [3,4]. Indolamine-2,3-dioxygenase (IDO) is usually a cytosolic enzyme that catalyzes tryptophan. IDO converts the amino acid tryptophan to L-kynurenine [5]. The depletion of tryptophan and the production of L-kynurenine induces the apoptosis of T-cells and natural killer (NK)-cells [6,7,8]. In addition, the IDO-expressing macrophages, dendritic cells, and tumor cells suppress T-cell proliferation [7,8,9,10]. In previous reports, IDO expression and the serum concentration of L-kynurenine were negative prognostic factors in diffuse large B-cell lymphomas and adult T-cell leukemia/lymphomas [11,12,13]. In a previous immunohistochemical analysis for IDO expression in diffuse large B-cell lymphomas treated with R-CHOP chemotherapy, the IDO-positive group showed resistance to the treatment and a poorer prognosis than the IDO-negative group [14]. Immunohistochemistry is a fast and inexpensive utility in diagnostic surgical pathology relatively. Immunohistochemistry is trusted for subtyping of lymphomas and performs an important function in hematopathology. There have become few latest immunohistochemical assays of IDO in lymphomas [14,15,16]. To handle different immunohistochemical features in a variety of lymphomas, we performed immunohistochemistry of IDO within a Korean lymphoma cohort of an individual center. 2. Methods and Materials 2.1. Research Population Rabbit polyclonal to IGF1R This research was accepted by the Institutional Review Panel (IRB) of Samsung Changwon Medical center, Changwon, Korea (IRB Document No. 2020-01-003, 23 January 2020). The scholarly research was retrospective, the IRB waived the necessity for written informed consent therefore. January 2014 and Dec 2019 were gathered The medical records of Samsung Changwon Medical center between. All Arry-520 (Filanesib) slides Arry-520 (Filanesib) of diagnosed lymphomas through the period had been independently evaluated by two writers (H.Y.T and L.I.P) based on the Globe Health Firm (Who have) classification of tumors of hematopoietic and lymphoid tissue, 4th Model. Of a complete of 171 situations attained by biopsy or excision, people that have an insufficient amount of specimen (cut off: 0.25 cm2) and cases of controversial diagnosis were excluded from the study. The remaining 120 cases were enrolled in this study (Male:Female = 5:3; aged 10C86, imply = 59.4 years, median = 62 years). Of the 120 cases of lymphoma, 103 cases were Ann Arbor stage I, 12 cases were stage II, and five cases were stage III. In situ hybridization (ISH) with the Epstein-Barr computer virus (EBV)-encoded small RNA (EBER) were performed in 91 cases of lymphoma. A total of 26.4% (24/91) of cases showed positivity for ISH with EBER (Hodgkin Lymphoma: five, EBV-Positive diffuse large B-cell lymphoma (DLBCL), not otherwise specified (NOS): two, Extranodal NK-/T-cell Lymphoma: twelve, Peripheral T-cell Lymphoma, NOS: three, Angioimmunoblastic T-cell Lymphoma: one, Enteropathy-associated T-cell Lymphoma, Type II: one). All cases were unfavorable for HIV contamination. All specimens were obtained at the time of Arry-520 (Filanesib) pathologic diagnosis before initiation of treatment. A total of seven cases of Hodgkin lymphoma, 77 cases of mature B-cell lymphoma, one B-Lymphoblastic lymphoma, and 35 cases of mature T- and NK-cell neoplasm were enrolled the study. 2.2. Immunohistochemistry for Indoleamine 2, 3-Dioxygenase We examined all slides of the cases and selected one representative formalin-fixed, paraffin-embedded (FFPE) block from each case for immunohistochemistry. The representative blocks were cut on 4 m solid sections and immunohistochemical staining was performed for Indoleamine 2, 3-dioxygenase (rabbit recombinant monoclonal,.