The classification of B-lineage acute lymphoblastic leukemia (ALL) by specific chromosomal translocations has prognostic implications for risk-directed therapy. Reverse transcription-polymerase chain reaction (RT-PCR) assay is a useful tool for detecting fusion transcripts from common chromosomal translocations of ALL cells. Multiplex RT-PCR and nested-PCR assays were used to detect ALL-type BCR-ABL1 transcripts of the t(9;22), TCF-PBX1 transcripts of t(1;19), the MLL-AF4 transcripts of t(4;11), and 2 variants of ETV6-RUNX1 of the cryptic t(12;21) in 148 leukemic samples upon diagnosis. The patients received risk-directed protocols of the Taiwan Pediatric Oncology Group-ALL-2002 that consisted of multiple chemotherapeutic agents of different intensities. Event-free survival (EFS) and overall survival (OS) rates were analyzed for genetic abnormalities detected by multiplex PCR and conventional cytogenetic analysis by the Kaplan-Meier method, and compared with the Mantel-Haenszel test. The Cox proportional hazards model was implemented to identify independent prognostic factors for EFS and OS. In this cohort of Taiwanese children, the relative frequencies of the 4 translocations of B-lineage ALL were 8% with ALL-type t(9;22)/BCR-ABL1, 4% with (1;19)/TCF-PBX1, 2% with t(4;11)/MLL-AF4, and 17.6% with t(12;21)/ETV6-RUNX1. Patients with t(12;21)/ETV6-RUNX1 fusion, hyperdiploidy, and t(1;19)/TCF-PBX1 fusion had the most favorable outcomes, whereas those with the t(9;22)/BCR-ABL1 fusion or t(4;11) and other MLL gene rearrangement had poor prognosis (P<0.001 for EFS and OS). BCR-ABL1, MLL gene rearrangement, and very high-risk group were independent prognostic factors after Cox regression analysis. The biological factors of leukemia cells are associated with treatment outcomes in childhood ALL. Multiplex RT-PCR assay is an efficient and sensitive diagnostic tool that may improve the ability to accurately and rapidly risk-stratify children with ALL.

Gene therapy for hemophilia B offers the advantage of a single administration with sustained therapeutic effects. This study evaluated the systemic safety, efficacy, biodistribution, and immunogenicity of AAV8-FIX-TripleL, a recombinant adeno-associated virus type 8 (AAV8) vector encoding a modified factor IX (FIX) variant with increased activity. In this good laboratory practice (GLP)-compliant study, 180 male FIX-knockout hemophilia B mice were randomized into 12 groups (n = 15) and received intravenous AAV8-FIX-TripleL at therapeutic (5 × 10¹¹ VG/kg) or supraphysiological (5 × 10¹² VG/kg) doses on Day 1. The mice were sacrificed on Days 2, 15, 28, and 91 for comprehensive evaluations, including hematological and biochemical assessments, histopathological examination, FIX protein/activity analysis, immunogenicity assessment, and vector biodistribution via quantitative polymerase chain reaction (qPCR) in major organs. AAV8-FIX-TripleL demonstrated dose-dependent increases in FIX activity and protein levels, with FIX activity exceeding physiological levels and the maintenance of a favorable safety profile. Biodistribution analysis confirmed predominant hepatic accumulation and vector persistence up to 91 days post-injection, with minimal off-target distribution. These findings indicate that AAV8-FIX-TripleL is a promising gene therapy candidate for hemophilia B, as it has robust expression, sustained efficacy, and a favorable safety profile, and that further translational studies are warranted.