Abstract 2775: Investigating myeloid-derived suppressor cells (MDSC) gene expression in predicting outcome in stage matched colorectal cancer patients

Abstract

Colorectal cancer (CRC) has emerged as the third most commonly diagnosed cancer in males and second most common in females. Although surgery, chemotherapy, and emerging immunotherapies have reduced mortality rates, tools that can assist in tailoring individualized treatments are needed. MDSC are immune-suppressive cells that interfere with the functioning of T cells and immune-inflammatory pathways. An extensive literature search identified 8 MDSC-centric genes which were tested for their prognostic significance in CRC. These genes; CEBPB, IL10, NOS2, RORC, S100A8, SOCS1, SOCS3, and TGFB1, along with their expression in tumor microenvironments could give new insights when correlated with clinical-pathologic features of colon cancer patients. The aim of the study is to quantify MDSC gene signatures in colorectal cancer patients. Under an IRB approved protocol, a total of 750 colon cancer patients at the Medical College of Georgia with 5 years of follow-up were initially selected. A total of 88 patients fit in our inclusion criteria, on the basis of survival duration after diagnosis. The FFPE blocks were acquired and patients were stratified on the basis of overall survival in two groups, with higher (>5 years) and lower survival (<1 year), as well as AJCC staging (I to IV), grade, gender and age. Total RNA was isolated and quantified through Nanodrop method. The statistical analysis of data was performed using student t-test and Pearson correlation. SOCS1 (p = 0.00*) was expressed in higher levels in patients with high survival (>5 years). Patients with low expression of TGFB1 survived longer compared to high expression group (p = 0.02*). On race comparison, CEBPA (p = 0.01*) showed significant expression in Caucasian population while NOS2 (p = 0.01*) expressed at higher levels in African Americans. These findings points to the clinical significance of MDSC based genes and tested the utility of a MDSC-related gene expression based prognostic biomarker panel for CRC patients. Citation Format: Saleh G. Heneidi, Chance Bloomer, Pankaj Ahluwalia, Ashis Mondal, Ravindra Kolhe. Investigating myeloid-derived suppressor cells (MDSC) gene expression in predicting outcome in stage matched colorectal cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2775.