Tyr705 phosphorylation, which is vital for STAT3 dimerization and is prevalent in prostate cancer (Horinaga et al., 2005; Liu et al., 2012; Bosch-Barrera and Menendez, 2015), was demonstrated to be downregulated by both compounds, followed by reduced STAT3 transcriptional activity. Here, STAT3 is linked to prostate cancer.