STAT3 and infection: Although it is not well understood if NF-κB and STAT3 are activated during HTLV-1 de novo infection, we speculate that NF-κB and STAT3 are activated, as NF-κB and STAT3-regulated inflammatory molecules, including IFN-γ, IL-1, TNF-α, IL-6 and CXCL10, are produced during HTLV-1 de novo infection [80].