Mapping the RNA-seq reads to the proviral and host reference genomes revealed in all tumours the complete absence of viral 5′LTR-dependent sense transcripts (5′S) (corresponding to the GAG, POL, ENV structural genes and the regulatory genes including TAX), yet abundant 3′LTR-dependent antisense transcripts corresponding to the previously described HTLV-1 HBZ and BLV AS1/2 RNAs11, 22, 24 (Fig. 2a and Supplementary Fig. 3). Here, CNTN2 is linked to neoplasm.