Abstract
Previous studies have revealed the aberrant expression of a number of microRNAs (miRNA/miRs) in the blood circulation of patients with breast cancer (BC). The aim of the present study was to assess the effect of neoadjuvant chemotherapy on the levels of a panel of BC-associated miRNAs, which are at relatively low (let-7, miR-10b, miR-34, miR-155, miR-200c and miR-205) or abundant (miR-21, miR-195 and miR-221) levels in the circulation. Patients with primary operable or locally advanced BC were enrolled in the study. The plasma levels of the miRNAs at baseline and at the fourth cycle of treatment were compared. Patients with stage II disease exhibited higher basal miRNAs levels than those with higher stages. The difference was most evident for miR-155 and miR-21 (P=0.05). From the initial to the fourth cycle of chemotherapy, the miRNA levels changed substantially. In samples in which the miRNA levels generally declined, a marked decrease (≤15,500-fold) was evident for the abundant miRNAs. Notably, the occurrence of a decrease in miRNA levels was more frequent in patients with smaller tumor sizes (P<0.05 for miR-21 and miR-195). This proof-of-concept study provides evidence that highly expressed miRNAs are affected most frequently by chemotherapy, particularly in patients with early stage tumors. This information may be valuable in assessing the response of the patients to therapy.
Highlights
Breast cancer (BC) is the most frequently diagnosed cancer and the leading cause of cancer‐related mortality among females worldwide [1]
Pretreatment plasma levels of miRNAs and their association with clinicopathological parameters. miR‐21, miR‐221 and miR‐195 had the highest basal expression levels in the blood plasma, while other miRNAs were expressed at much lower levels (Fig. 1A)
The association between the pretreatment miRNA levels and clinicopathological parameters were investigated, and the plasma levels of all miRNAs were observed to be higher in the patients with stage II tumors (n=13) than in those with higher tumor stages (Fig. 1B and C)
Summary
Breast cancer (BC) is the most frequently diagnosed cancer and the leading cause of cancer‐related mortality among females worldwide [1]. This high heterogeneity is associated with significant challenges in BC management, and these molecular features are key factors in the response to therapy and disease outcome
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call