Is microRNA-31 a key regulator of breast tumorigenesis?

To date, investigation of microRNA (miRNA) is still attractive trend in molecular oncology due to a large number of known miRNA sequences, hence their function in tumorigenesis is unexplored for majority. Involvement of miRNA in various cell pathways and alteration of their expression observed in cancer emphasizes key role of miRNA in cell cycle regulation and in tumor development. For the few years alteration of those small non-coding RNA is carefully tested in various human neoplasms as potential tumor drivers and missing piece in triggering process of malignant transformation (1,2). Exploring role of selected miRNA can contribute to understanding their function in malignant transformation including regulation of breast tumorigenesis.