Correlation of myeloid derived suppressor cell (MDSC) populations with clinicopathologic features in urothelial carcinoma (UC).

Abstract

434 Background: MDSC are a heterogeneous population of potent immunosuppressive cells with potential predictive/prognostic significance in solid tumors. The association between MDSC and clinicopathologic features in patients (pts) with UC was investigated. Methods: Peripheral blood from 26 non-metastatic UC pts scheduled to undergo cystectomy or nephroureterectomy at Cleveland Clinic was collected. MDSC were enumerated in fresh unfractionated blood (WB) and in peripheral blood mononuclear cells (PBMC). (T)otal MDSC were defined as CD33+/HLADR-; out of T-MDSC, (G)ranulocytic (CD15+CD14-), (M)onocytic (CD15-CD14+) and (I)mmature (CD15-CD14-) MDSC were identified. CD11b MDSC (Linlo/HLADR-/CD33+/CD11b+) were identified in WB. MDSC populations were presented as % of live nucleated blood cells and as absolute numbers from WB. Wilcoxon rank sum test was used to assess associations between MDSC populations and clinicopathologic features. Due to the exploratory nature of the study, p &lt; .10 was considered significant. Results: Of 26 pts, 25 had surgery and 1 is under surveillance. 24 had both WB and PBMC data. 23/26 were men; median age 67. Of 26 pts, all had primarily UC histology; 7 had mixed UC histology, 11 had prior intravesical BCG, 12 neoadjuvant therapy (10 Gem/Cis, 1 Gem/Carbo, 1 unknown). Of 25 pts who had surgery, 5 had pT3/4 stage; 5 had LVI; 9 had CIS. All but 1 had negative LN. Higher levels of specific WB MDSC populations were associated with mixed histology (including squamous), CIS, and higher pT-stage (Table). When compared to a separate cohort of 11 pts with metastatic UC, the % G-MDSC in PBMC was lower in non-metastatic pts (median 0.3 vs. 1.47; p = .05). Conclusions: Although no single MDSC population correlated with all the evaluated clinicopathologic features, higher levels of certain MDSC populations appear to correlate with histology and pT stage. Further validation of blood and tissue is ongoing in a larger cohort. [Table: see text] </jats:p