Kim Schach

Myeloid-derived suppressors cells (MDSC) correlate with clinicopathologic factors and pathologic complete response (pCR) in patients with urothelial carcinoma (UC) undergoing cystectomy

BACKGROUND Myeloid derived suppressor cells (MDSC) are heterogeneous immunosuppressive cells with potential predictive and prognostic roles in cancer. The association between MDSC, clinicopathologic factors, and pathologic response in patients with bladder urothelial carcinoma (UC) was explored. METHODS Peripheral blood or tissue were collected from patients with UC undergoing definitive surgery. MDSCs levels were measured in peripheral blood mononuclear cells and fresh tumor tissue. MDSCs were identified by flow cytometry and defined as total MDSC (T-MDSC) CD33+/HLADR-. From this population, 3 subsets were identified: polymorphonuclear-MDSC (PMN-MDSC) defined as CD33+/HLADR-/CD15+/CD14-, monocytic-MDSC (M-MDSC) defined as CD33+/HLADR-/CD15-/CD14+, and immature-MDSC (I-MDSC) defined as CD33+/HLADR-/CD15-/CD14-. MDSC populations were presented as % of live nucleated blood cells. Spearman correlations (r) and Wilcoxon rank sum test were used to assess correlations between MDSC populations, clinicopathologic factors, and pathologic complete response (pCR). RESULTS 85 patients scheduled to undergo cystectomy from February 2015 through Dec 2016 were included. All patients had blood drawn for analysis and 23 patients had residual tumor tissue collected for analysis at the time of surgery. Of these 85, 74 (87%) were men with a median age at diagnosis of 68 (range: 44-87). Pure UC was the most common histology (75%); 28 (35%) patients had prior treatment with intravesical therapy and 36 (42%) were treated with neoadjuvant chemotherapy, primarily gemcitabine plus cisplatin (n = 24). On surgical pathology, 18 (21%) of the patients had pCR, 11 (13%) had positive lymph nodes, and 20 patients (24%) had lymphovascular invasion. Statistically significant associations were found between circulating MDSC levels and pCR rates (P<0.01), absolute neutrophil-lymphocyte ratio (P = 0.008), and histology (P = 0.01). Tumor % M-MDSCs were negatively associated with lymphovascular invasion (P = 0.04). There were no significant correlations between peripheral blood mononuclear cells and tumor MDSC subtypes. CONCLUSIONS Blood and tissue MDSC levels correlate with several clinicopathologic factors and may predict for pCR. Future studies are needed to highlight the role of MDSC in predicting long-term outcomes and to determine the clinical implications of these findings.

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

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 < .10 was considered significa...