In addition to regulating Lin28, let‐7 miRNAs directly target and repress the expression of Irs2 (Zhu et al, 2011), a positive regulator of cell proliferation upregulated in liver, pancreas, and prostate cancer (Mardilovich & Shaw, 2009; Mardilovich et al, 2009). Here, IRS2 is linked to Familial prostate cancer.