MicroRNAs (miRNAs) are key regulators in immune surveillance and immune escape as well as modulators in the metastatic process of breast cancer cells. We evaluated the differential expression of plasma miR-10b, miR-19a, miR-20a, miR-126 and miR-155, which regulate immune response in breast cancer progression and we investigated their clinical relevance in the outcomes of breast cancer patients. Plasma samples were obtained from early (eBC; n = 140) and metastatic (mBC; n = 64) breast cancer patients before adjuvant or first-line chemotherapy, respectively. Plasma miRNA expression levels were assessed by qRT-PCR. We revealed a 4-miRNA panel consisted of miR-19a, miR-20a, miR-126, and miR-155 able to discriminate eBC from mBC patients with an AUC of 0.802 (p < 0.001). Survival analysis in eBC patients revealed that low miR-10b and miR-155 expression was associated with shorter disease free survival (disease free survival; p = 0.012 and p = 0.04, respectively) compared to high expression. Furthermore, miR-126 expression was associated with shorter overall survival (overall survival; p = 0.045). In multivariate analysis the number of infiltrated axillary lymph nodes and low miR-10b expression independently predicted for shorter DFS (HR: 2.538; p = 0.002 and HR: 1.943; p = 0.033, respectively) and axillary lymph nodes and low miR-126 for shorter OS (HR: 3.537; p = 0.001 and HR: 2.558; p = 0.018). In the subgroup of triple negative breast cancer (TNBC) patients, low miR-155 expression independently predicted for shorter DFS (HR: 5.056; p = 0.037). Accordingly in mBC, patients with low miR-10b expression had shorter progression free survival and OS compared to patients with high expression (p = 0.0017 and p = 0.042, respectively). In multivariate analysis, recurrent disease and low miR-10b expression independently predicted for shorter PFS (HR: 2.657; p = 0.001 and HR: 1.920; p = 0.017, respectively), whereas performance status two independently predicted for shorter OS (HR: 2.031; p = 0.03). In summary, deregulated expression of circulating miRNAs involved in tumor and immune cell interactions evaluated before adjuvant and 1st-line chemotherapy can distinguish disease status and emerge as independent predictors for outcomes of breast cancer patients.

e15528 Background: MicroRNAs (miRNAs) are involved in the regulation of immune response and have an important role in immune escape. We analyzed the expression levels of plasma miR-10b, miR-126, miR-19α, miR-20α and miR-155, which regulate tumor-immune interactions and investigated their prognostic implications in patients with early (eBC) and metastatic (mBC) breast cancer. Methods: Blood samples were obtained before treatment from 140 and 64 patients with eBC and mBC, respectively. Plasma miRNA expression levels were assessed by qRT-PCR and expression was classified as high or low according to the median values. Results: A panel of four miRNAs (miR-19a, miR-20a, miR-126 and miR-155) could discriminate eBC from mBC (AUC 0.802, p < 0.001). In early disease, miR-10b (p = 0.022) and miR-155 (p = 0.005) expression was lower in relapsed (n = 46) compared to non-relapsed (n = 94) patients; miR-155 expression along with lymph node infiltration and tumor grade had increased ability to predict relapse (AUC = 0.775; p = 0.003). In addition, miR-10b (p = 0.015), miR-19a (p = 0.003), miR-20a (p = 0.012), miR-126 (p = 0.001) and miR-155 (p < 0.001) expression levels were lower in patients with early relapse (relapse at ≤2 years). MiR-155 and miR-19a had the highest performance in discriminating early relapse (AUC 0.855; p < 0.001 and AUC = 0.729; p = 0.003, respectively), whereas, combined mir-155 and miR-19a expression further increased the accuracy of prediction (AUC = 0.867; p < 0.001). In eBC, the number of infiltrated lymph nodes and low miR-10b independently predicted for shorter DFS (p = 0.001 and p = 0.03, respectively) and axillary lymph nodes for shorter OS (p = 0.003). In the triple negative subgroup, low miR-155 strongly predicted for shorter DFS (p = 0.037). In mBC, recurrent disease and low miR-10b expression independently predicted for shorter PFS (p = 0.001 and p = 0.017, respectively), whereas performance status of 2 independently predicted for shorter OS (p = 0.03). Conclusions: Deregulated expression of circulating miRNAs involved in tumor-immune interactions can discriminate disease status in BC and independently predicts for patients’ outcome in early and mBC. Our results further support the notion that circulating miRNAs represent a useful prognostic tool in patients with BC.

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MicroRNAs (miRNAs) are involved in the regulation of immune response and hold an important role in tumor immune escape. We investigated the differential expression of the immunomodulatory miR-10b, miR-19a, miR-20a, miR-126, and miR-155 in the plasma of healthy women and patients with early stage breast cancer and interrogated their role in the prediction of patients’ relapse. Blood samples were obtained from healthy women (n = 20) and patients with early stage breast cancer (n = 140) before adjuvant chemotherapy. Plasma miRNA expression levels were assessed by RT-qPCR. Relapse predicting models were developed using binary logistic regression and receiver operating curves (ROC) were constructed to determine miRNA sensitivity and specificity. Only miR-155 expression was lower in patients compared with healthy women (p = 0.023), whereas miR-155 and miR-10b were lower in patients who relapsed compared with healthy women (p = 0.039 and p = 0.002, respectively). MiR-155 expression combined with axillary lymph node infiltration and tumor grade demonstrated increased capability in distinguishing relapsed from non-relapsed patients [(area under the curve, (AUC = 0.861; p < 0.001)]. Combined miR-19a and miR-20a expression had the highest performance in discriminating patients with early relapse (AUC = 0.816; p < 0.001). Finally, miR-10b in combination with lymph node status and grade had the highest accuracy to discriminate patients with late relapse (AUC = 0.971; p < 0.001). The robustness of the relapse predicting models was further confirmed in a 10-fold cross validation. Deregulation of circulating miRNAs involved in tumor-immune interactions may predict relapse in early stage breast cancer. Their successful clinical integration could potentially address the significance challenge of treatment escalation or de-escalation according to the risk of recurrence.

Background: Metastasis remains the major lethal consequence in the progression of early breast cancer (BC). Effective immunosurveillance can inhibit metastasis, while a dysfunctional immune system can create a favorable environment for tumor spread. MicroRNAs (miRNAs) are involved in the regulation of immune response and there is evidence that they play an important role in immune escape. We investigated the effect of plasma miR-10b, miR-126, miR-19α, miR-20α and miR-155, which regulate the interaction between cancer and immune cells during immunosurveillance and immune evasion in patients with early BC. Methods: Blood samples were obtained from relapsed (n=52) and non-relapsed (n=100) patients with early BC before adjuvant chemotherapy. Plasma miRNA expression levels were assessed by qRT-PCR and expression was classified as high or low according to the median values. Receiver operating curves (ROC) were constructed to determine miRNA sensitivity and specificity. Results: miRNA expression was not correlated with patients’ characteristics or outcome. No differences in miRNA expression were observed between relapsed and non-relapsed patients. In multivariate analysis the number of infiltrated axillary lymph nodes and stage III disease independently predicted for shorter DFS (HR: 2.591; p=0.002) and OS (HR: 2.344; p=0.035), respectively. miR-126, miR-20a, miR-19a and miR-155 expression levels were lower in patients with early relapse (defined as relapse at ≤ 2 yrs; n=19) compared to those who either relapse later than 2 years (n=33) or those who remained disease-free during follow up (n=100). ROC curve analysis showed that miR-155 had the highest performance to discriminate patients with early relapse [AUC 0.825; sensitivity 90%, specificity 67% (p&lt;0.001; 95% CI: 0.742-0.909)]. Multivariate analysis revealed that ER negative status and miR-155 low expression independently predicted for shorter DFS (HR: 2.616; p=0.039 and HR: 9.104; p=0.003, respectively). For the triple negative subgroup (n=31), low miR-155 expression was associated with both shorter DFS and OS (p=0.02 and p=0.032, respectively) and low miR-155 expression was an independent predictor of shorter DFS (HR: 5.056; p=0.037). Conclusions: Deregulated expression of circulating miRNAs involved in tumor and immune cell interactions evaluated before adjuvant chemotherapy is associated with early relapse in patients with primary BC. Low miR-155 expression has high accuracy in the prediction of early relapse in the whole group of patients and independently predicts for shorter DFS in the triple negative subgroup. The role of miR-155 in the pathogenesis and management of early relapse in BC merits further investigation. Citation Format: Konstantina Thomopoulou, Chara Papadaki, Alexia Monastirioti, George Koronakis, Lambros Vamvakas, Maria A Papadaki, Sofia Agelaki, Dimitrios Mavroudis. microRNAs regulating tumor and immune cell interactions in the prediction of early relapse in breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P1-05-07.