CNTN2 and adult T-cell leukemia/lymphoma: Anti-sense RNAs containing the HTLV-1 LTR region, and RNA from the Rex-responsive element in the LTR have been proposed to regulate NF-κB activation by stimulating pattern recognition receptors (PRRs) such as RNA-dependent protein kinase (PKR) and 2’5’-oligoadenylate synthetase, an interferon stimulated gene (ISG), in Tax-negative ATLL cells [251,252].