IFNA1 and adult T-cell leukemia/lymphoma: Zidovudine (AZT), a pyrimidine synthetic analog belonging to the class of nucleoside reverse transcriptase inhibitors (NRTIs), is recommended for first-line therapy for all clinical subtypes of ATLL in combination with interferon-alpha (IFN-α), with concomitant chemotherapy reserved for the lymphoma subtype.