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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.

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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.

Despite the development of new treatment options based on the molecular characterization of colorectal cancer, 20% of patients present de novo metastatic disease, whereas 30-40% of patients who receive curative treatment relapse during follow up. Herein, we report 2 cases with rectal cancer that developed uncommon sites of metastasis; the first patient had an isolated breast metastasis, while the second patient developed bone marrow infiltration with synchronous brain metastases. In order to evaluate the uncommon metastatic pattern of rectal cancer, we detected and enumerated circulating tumor cells (CTCs) using both immunofluorescence and real-time reverse transcriptase polymerase chain reaction in these patients’ peripheral blood. The procedure revealed the presence of CTCs, positive for CEACAM5 but negative for epithelial phenotype (EpCAM-), that might explain the patients’ metastatic potential and survival.