This study identified recurring region of deletion harboring genes CDKN2A, CDKN2B, LEF1, PTEN, RBI, and STIL. In terms of uniparental disomy (UPD), the T-ALL lacked whole chromosome UPD, but showed segmental UPDs (sUPDs) in 42% of cases, with a high proportion of sUPD 9p (30% of the cases) associated with homozygous CDKN2A deletion. This evidence concerns the gene LEF1 and acute lymphoblastic leukemia.