FOS and adult T-cell leukemia/lymphoma: Considering the known activation of AP-1 by HTLV-1 Tax as well as the constitutive activation of AP-1 in primary ATLL cells [44], it is possible that the suppression of AP-1 inhibitors such as BTB and CNC homology 1 (BACH1) by miR-155 may derepress AP-1 promoter activity [45].