Ornstein MC, et al. - Researchers explored the association between MDSC, clinicopathologic factors, and pathologic response in patients with bladder urothelial carcinoma (UC). MDSC levels had statistically significant associations with pCR rates, absolute neutrophil-lymphocyte ratio, and histology. Tumor % M-MDSCs showed a negative association with lymphovascular invasion. Findings thereby suggest that blood and tissue MDSC levels have correlation with several clinicopathologic factors and may predict for pCR.

Methods

• From patients with UC undergoing definitive surgery, peripheral blood or tissue were collected.
• Researchers measured MDSCs levels in peripheral blood mononuclear cells and fresh tumor tissue.
• Using flow cytometry, MDSCs were identified; these were defined as total MDSC (T-MDSC) CD33+/HLADR-.
• Three subsets were identified from this population: 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.
• They assessed correlations between MDSC populations, clinicopathologic factors, and pathologic complete response (pCR) using Spearman correlations (r) and Wilcoxon rank sum test.

Results

• From February 2015 through Dec 2016, 85 patients [74 (87%) were men and a median age at diagnosis was 68 (range: 44–87)] scheduled to undergo cystectomy; these were included in this study.
• All patients underwent blood analysis; 23 patients had residual tumor tissue collected for analysis at the time of surgery.
• The most common histology was pure UC (75%); 28 (35%) patients had prior treatment with intravesical therapy and 36 (42%) were treated with neoadjuvant chemotherapy, primarily gemcitabine plus cisplatin (n = 24).
• Eighteen (21%) of the patients had pCR, 11 (13%) had positive lymph nodes, and 20 patients (24%) had lymphovascular invasion on surgical pathology.
• Between circulating MDSC levels and pCR rates (P < 0.01), absolute neutrophil-lymphocyte ratio (P=0.008), and histology (P=0.01) statistically significant associations were observed.
• Tumor % M-MDSCs showed a negative association with lymphovascular invasion (P = 0.04).
• Between peripheral blood mononuclear cells and tumor MDSC subtypes, no significant correlations were identified.