In this study, a careful analysis including weighted gene co-expression analysis and machine learning revealed 5 genes including FBXO9, ZNF526, ERCC8, WDR5, and XRCC3 for HAM/TSP, and 13 genes including PAIP1, BCAS2, COPS2, CTNNB1, FASLG, GTPBP1, HNRNPA1, RBBP6, TOP1, SLC9A1, JMY, PABPC3, and PBX1 in ATLL. This evidence concerns the gene BCAS2 and adult T-cell leukemia/lymphoma.