The mature microRNA products are thought to regulate expression levels of other genes through complementarity to the 3' UTR of specific target messenger RNA.

[2][3] The paralogous miRNA gene clusters that give rise to miR-17 family microRNAs (miR-17~92, miR-106a~363, and miR-106b~25) have been implicated in a wide variety of malignancies and are sometimes referred to as oncomirs.

[4] The oncogenic potential of these non-protein encoding genes was first identified in mouse viral tumorigenesis screens.

[5][6][7] In humans, the activating mutations of miR-17~92 have been identified in non-Hodgkin's lymphoma, whereas the miRNA constituents of the clusters are overexpressed in a multiple cancer types.

[12][13] miR-20a detection in human faeces could be a non-invasive screening marker for colorectal cancer.