Abstract A56: The number of MDSC (Gr1+/CD11b+) and T lymphocytes in blood of canine patients during mammary and skin tumors development.

Abstract

Abstract The very recent studies have indicated an important role of myeloid derived suppressor cells (MDSC) in the tumor progression and metastasis. They are thought to suppress the immune system and promote angiogenesis via STAT3 activation. The aim of present study was two-fold: 1) to assess the percentage of MDSCs (CD11b+/Gr1+) in canine blood leukocytes and percentage of MDSCs that express p-STAT3 at high level; and 2) to assess the percentage of CD3+, CD4+, CD8+ and Treg (CD4+/FoxP3+) in canine blood lymphocytes collected from patients with various clinical stage of mammary and skin tumors comparing to control healthy dogs. The samples were analyzed using BD FACS AriaII. The results of our study indicate that percentage of Gr1-positive cells is significantly increased (p<0.05) in patients with stage IV tumor (4.6%, compared to control and stage I, II and III tumor: 2.38%, 0.8%, 0.65%, 1.2%, respectively). The number of Treg cells was significantly decreased (p<0.001) in patients with stage III and IV tumor (1.06% and 1.03%, respectively) compared to control (4.82%), stage I and II tumor (6.5% and 3.95%, respectively). Similarly, the number of CD4+ cells was significantly decreased (p<0.01 and p<0.001) in stage III and IV tumors (14.8% and 2.27%, respectively) compared to control (29.84%), and stage I and II tumors (26.20% and 18.75%, respectively). Thus, the ratio of CD4/CD8 was also significantly decreased (p<0.01 and p<0.001) in stage III and IV tumors (respectively). The number of CD3+ cells was also significantly (p<0.01) decreased in stage III and IV tumors (5.23% and 4.46%, respectively), comparing to control (11.66%), and stage I and II tumors (13.57% and 7.4%). Our results indicate significant immunosuppression in patients with advanced tumors that can be related to high MDSCs level. High level of these cells may be also related with metastasis formation in patients with advanced tumors. This work was supported by grant no IP2011 027171 from the Ministry of Sciences and Higher Education. Citation Format: Joanna Mucha, Agata Homa, Kinga Majchrzak, Tomasz Motyl, Magdalena Król. The number of MDSC (Gr1+/CD11b+) and T lymphocytes in blood of canine patients during mammary and skin tumors development. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology: Multidisciplinary Science Driving Basic and Clinical Advances; Dec 2-5, 2012; Miami, FL. Philadelphia (PA): AACR; Cancer Res 2013;73(1 Suppl):Abstract nr A56.