Abstract P5-07-10: Circulating microRNAs as early predictors of relapse in operable breast cancer

Abstract

Abstract Background: Metastasis remains a major threat for patients (pts) with operable breast cancer (BC). Recurrence could arise from a state of tumour dormancy during which there is growth restriction of undetectable micrometastases. The expression of dormancy and metastasis related miRNAs was evaluated in the plasma of pts with operable BC obtained before adjuvant therapy in order to discover novel biomarkers for the prediction of relapse. Methods: Plasma miR-21, miR-23b, miR-190, miR-200b and miR-200c expression was assessed by qRT-PCR in 133 pts with early BC (non-relapsed, n=84; relapsed, n=49). Expression was classified as high or low according to the median values and was associated with pts' clinicopathological characteristics and clinical outcome. Results: No correlation was observed between the expression of miRNAs and the clinicopathological characteristics of pts. After a median f-up of 90.5 mo, median Disease Free Interval (DFI) was significantly lower in pts with high compared to low miR-21 [105 mo vs not reached (NR); p=0.001], miR-200c (105.2 mo vs NR; p=0.007), or both miR-21 and miR-200c expression (81.37 mo vs NR; p=0.001). miR-21-high was also associated with decreased median Overall Survival (OS; p=0.041). In multivariate analysis the number of infiltrated axillary lymph nodes (N3 vs N0-N2, HR: 2.86; p= 0.004) and miR-21 expression (high vs low, HR: 2.824; p=0.001) were independent negative prognostic factors for DFI, whereas negative hormone receptor status (HR: 3.062; p=0.024) and miR-21 high (HR: 3.545; p=0.029) independently predicted for worse OS. Moreover, miR-21 expression was higher in pts presenting early relapse (defined as relapse at ≤ 3 yrs) compared to those without relapse at 5 yrs (p=0.032). Furthermore, higher miR-21 (p=0.038), miR-23b (p=0.039), miR-200b (p=0.027) and miR-200c (p<0.001) levels were observed in pts with late relapse (at ≥ 5 yrs) compared to those without relapse. Conclusions: Differential expression levels of metastasis and/or dormancy related circulating miRNAs are encountered before adjuvant therapy in pts with operable BC presenting subsequent relapse compared to non-relapsed pts. In addition, circulating miRNAs could predict for early or late recurrence years before clinical detection of metastases. These results merit prospective validation in an independent pt cohort. Citation Format: Agelaki S, Papadaki C, Stratigos M, Spiliotaki M, Markakis G, Mastrostamatis G, Mavroudis D, Ioannis S. Circulating microRNAs as early predictors of relapse in operable breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-07-10.