PT - JOURNAL ARTICLE AU - Kitano, Shigehisa AU - Postow, Michael A. AU - Ziegler, Carly G.K. AU - Kuk, Deborah AU - Panageas, Katherine S. AU - Cortez, Czrina AU - Rasalan, Teresa AU - Adamow, Mathew AU - Yuan, Jianda AU - Wong, Philip AU - Altan-Bonnet, Gregoire AU - Wolchok, Jedd D. AU - Lesokhin, Alexander M. TI - Computational Algorithm-Driven Evaluation of Monocytic Myeloid-Derived Suppressor Cell Frequency for Prediction of Clinical Outcomes AID - 10.1158/2326-6066.CIR-14-0013 DP - 2014 Aug 01 TA - Cancer Immunology Research PG - 812--821 VI - 2 IP - 8 4099 - http://cancerimmunolres.aacrjournals.org/content/2/8/812.short 4100 - http://cancerimmunolres.aacrjournals.org/content/2/8/812.full SO - Cancer Immunol Res2014 Aug 01; 2 AB - Evaluation of myeloid-derived suppressor cells (MDSC), a cell type implicated in T-cell suppression, may inform immune status. However, a uniform methodology is necessary for prospective testing as a biomarker. We report the use of a computational algorithm-driven analysis of whole blood and cryopreserved samples for monocytic MDSC (m-MDSC) quantity that removes variables related to blood processing and user definitions. Applying these methods to samples from patients with melanoma identifies differing frequency distribution of m-MDSC relative to that in healthy donors. Patients with a pretreatment m-MDSC frequency outside a preliminary definition of healthy donor range (<14.9%) were significantly more likely to achieve prolonged overall survival following treatment with ipilimumab, an antibody that promotes T-cell activation and proliferation. m-MDSC frequencies were inversely correlated with peripheral CD8+ T-cell expansion following ipilimumab. Algorithm-driven analysis may enable not only development of a novel pretreatment biomarker for ipilimumab therapy, but also prospective validation of peripheral blood m-MDSCs as a biomarker in multiple disease settings. Cancer Immunol Res; 2(8); 812–21. ©2014 AACR.