Circulating Cell-free miRNA Expression and its Association with Clinicopathologic Features in Inflammatory and Non-Inflammatory Breast Cancer

Recent discovery showing the presence of microRNAs (miRNAs) in the circulation sparked interest in their use as potential biomarkers. Our previous studies showed the diagnostic potential of miR-451 as a serological marker for inflammatory breast cancer (IBC), miR-337- 5p and miR-30b for non-inflammatory breast cancer (non-IBC). The aim of this study is to investigate the prognostic values of circulating miRNAs by comparing the amounts of 12 circulating miRNAs in the serum of IBC and non-IBC from Tunisian breast cancer patients, and by determinating whether correlated pairs of miRNAs could provide useful information in the diagnosis of IBC and non-IBC patients. TaqMan qPCR was performed to detect circulating expression of miRNAs in serum of 20 IBC, 20 non-IBC and 20 healthy controls. Nonparametric rank Spearman rho correlation coefficient was used to examine the prognostic value of miRNAs and to assess the correlation profile between miRNAs expression. Further, a large number of miRNAs were highly correlated (rho>0.5) in both patients groups and controls. Also, the correlations profiles were different between IBC, non-IBC and healthy controls indicating important changes in molecular pathways in cancer cells. Our results showed that miR-335 was significantly overexpressed in premenopausal non-IBC patients; miR-24 was significantly overexpressed in non-IBC postmenopausal patients. Patients with previous parity had higher serum of miR-342-5p levels than those without. Furthermore, patients with HER2+ IBC present lower serum levels of miR-15a than patients with HER2- disease. Together, these results underline the potential of miRNAs to function as diagnostic and prognostic markers for IBC and non-IBC, with links to the menopausal state, Her2 status and parity.