STAT3 and neoplasm: Collectively, the findings presented here suggest that HNK inhibits leptin-induced tumor progression and provide in vitro as well as in vivo evidence for the involvement of miR-34a as a regulator of HNK-mediated inhibition of Wnt1-MTA1-β-catenin axis, and uncover a novel mechanism of HNK action through inhibition of Stat3 leading to miR-34a activation (Figure 7).