MiRNA profiling in a case: Control study of African American women with uterine serous carcinoma (USC).

Abstract

e17116 Background: USC is an aggressive subtype of endometrial cancer associated with worse outcomes in African American patients. We evaluated differences in tumor miRNA expression by race, clinical and tumor characteristics, and survival outcomes. Methods: FFPE tumor tissue from hysterectomy specimens was identified for 29 African American cases. Case matching was performed by computer-based random assignment in a 1:1 ratio with Caucasian controls based on age ( < 70 vs. ≥70 years), stage (FIGO I/II vs. III/IV) and histologic subtype (pure vs. mixed). RNA was extracted from 77 specimens with sufficient tumor cellularity (54 tumors and 23 matched normal endometrium). miRNA array profiling was performed by microRNA Hi-Power Labeling (Hy3/Hy5) and hybridization to miRCURY LNA microRNA Array 7th Gen (Exiqon, Denmark). Analysis was performed with R/Bioconductor using a moderated t-statistic with multiple testing correction. Validation was done using the TCGA dataset. Results: Clinical and treatment characteristics were similar for cases and controls, although use of adjuvant radiation was less common in African Americans (p = 0.03). With a median follow-up of 43 months, 17 patients had recurrent or progressive disease. DFS and OS rates were similar by race (both logrank p > 0.5). Of 968 miRNAs analyzed, 649 were differentially expressed in normal endometrium vs. tumor. When compared by race, histologic subtype, stage or presence of LVI, no differentially expressed miRNAs were identified. In patients with disease recurrence at 3 years, miR-223 was significantly upregulated (fold change 1.5; p = 0.002). In validation using a TCGA dataset of 131 patients with mixed (n = 22) or pure serous (n = 109) histology, increased miR-223 expression ( > median) was associated with worse overall survival (HR 2.47; 95%CI 0.9-6.6). After adjustment for patient age and BMI, upregulation of miR-223 was a significant risk factor for death (adjusted HR 2.94; 95%CI 1.01-8.52). Conclusions: Upregulation of miR-223 was associated with disease recurrence in a cohort of women with uterine serous carcinoma and validated by TCGA data. miRNA profiling did not identify biological differences between African American and Caucasian patients.