We utilized the TargetScan database  to identify known and putative mRNA targets of mir-17~92 that are implicated in the regulation of ERK phosphorylation. We identified the dual specificity phosphatases DUSP2, DUSP7 and DUSP10, which are known to regulate MAP kinase phosphorylation, as potential targets of cluster-encoded miRNAs [49, 50]. However, immunostaining of PanIN lesions with antibodies against these phosphatases did not show any differences between mir-17~92 wild type and deficient PanINs (data not shown). Moreover, the enhanced ERK phosphorylation observed in PanIN cell lines following ectopic mir-17~92 expression was not associated with changes in DUSP7 or DUSP10 protein levels (Supplementary Figure 4). DUSP2 was undetectable by immunoblotting or qRT-PCR in these cell lines (data not shown). Thus, the detailed mechanisms regulating ERK phosphorylation in PanINs downstream of mir-17~92 remain unknown.