Recent studies have employed RNA in situ hybridization for HBZ [15] (located near the 3′ LTR and expressed in all ATLL cells) [16], and quantitative PCR amplification of the tax gene (located in the highly conserved pX region) using DNA extracted from FFPE tissue samples (tax-qPCR) [17]. Here, HBZ is linked to adult T-cell leukemia/lymphoma.