LTA and neoplasm: It is also noteworthy that a conserved LXCXE motif (thought to be involved in interactions with the pRb family of tumor suppressor proteins and suppression of innate antiviral immunity [31]) is located on the shared sT/LT leader sequence in the Avi and bandicoot viruses, whereas the LXCXE motif is instead located in the second exon of LT in Ortho and Almi species.