Expression and clinical significance of miRNAs that may be associated with the FHIT gene in breast cancer

• miR-663a and miR-668 expressions may be prognostic factors for clinicopathological features of breast tumors.
• miR-663a and miR-668 may regulate the expression of FHIT.
• Altered expression of miR-663a has been linked to loss of function of FHIT.

The dysregulation of miRNA expression has frequently been observed in breast cancer. Therefore, we investigated the expression profile of miRNAs that may be associated with expression of the FHIT gene in breast cancer and assessed their clinicopathological significance. The expression levels of miR-143, miR-663a, miR-668, miR-922 and FHIT were analyzed in normal and malignant breast tissues from 65 patients with breast cancer. We studied the correlation between the expression of miR-143, miR-663a, miR-668, miR-922 and FHIT and the clinicopathological features presented by the patients. The expression levels of the miRNAs and FHIT were downregulated in breast cancer tissue. The expression levels of miR-143, miR-663a and miR-668 were significantly reduced in FHIT downregulated tumors. miR-668 expression was also significantly altered relative to FHIT down- and up- regulated tumor tissues. Reduced miR-663a expression was statistically associated with high-grade ER/PR (+) status, benign reactive hyperplasia, lymph-node metastasis, in-situ component > 25% and Ki 67 > 15% compared with non-tumor tissues. Additionally, reduced miR-668 expression was significantly different between tumors with and without lymph-node metastasis. miR-668 may play an important role in breast cancer development and progression by regulating the expression of FHIT. Furthermore, miR-668 and miR-663a may be potential prognostic biomarkers for breast cancer.