CTCF and adult T-cell leukemia/lymphoma: Using CTCF Chip assays, Satou et al. observed that CTCF, a regulator of chromatin structure, bound to the so called pX region of HTLV-1 provirus in a nonmalignant HTLV-1 infected T cell clone and in a T cell line derived from adult T cell leukemia (ATL) (Satou et al., 2016).