XL TLX3 BA consists of an orange-labeled probe hybridizing proximal to the TLX3 gene region at 5q35.1 and a green-labeled probe hybridizing distal to the TLX3 gene region at 5q35.1.

Probe maps are created in accordance with the intended purpose of the product. Solid colored bars do not necessarily indicate that the probe fully covers the indicated genomic region. Therefore, caution is advised when interpreting results generated through off-label use. Probe map details based on UCSC Genome Browser GRCh37/hg19. Map components not to scale. Further information is available on request.

Acute lymphoblastic leukemia (ALL) is the most common childhood cancer type. T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive and quickly progressing type of ALL affecting T-lymphocytes. Genomic data suggests that more than 10 functional aberrations are contributing to the development of this disease. T-ALL cases can be grouped by distinct genetic profiles and the aberrant expression of a characteristic transcription factor. Major subgroups are characterized by ectopic expression of TAL1, TLX1, TLX3, HOXA9/10, LMO2 or NKX2-1 and others as a result of chromosomal rearrangements or mutations. About 20% of childhood T-ALL cases are characterized by aberrant expression of TLX3 as a result of t(5;14)(q35;q32). This cryptic translocation juxtaposes TLX3, normally not expressed in T-cells, with the BCL11B gene, which is active in T-cells, resulting in ectopic expression of TLX3.
Fluorescence in situ hybridization is a valuable method for the detection of t(5;14)(q35;q32) since cryptic translocations may escape during classical cytogenetic analysis. Furthermore, the broad range of breakpoints in the chromosomal region 14q32 makes the development of efficient PCR-based methods difficult.

Clinical Applications

• Acute Lymphoblastic Leukemia (ALL)

XL TLX3 BA hybridized to lymphocytes. One normal interphase and metaphase are shown.

• Van Zutven et al (2004) Haematologica 89:671-678
• Su et al (2006) Blood 108:4198-4201
• Girardi et al (2017) Blood 129:1113-1123

• Utility and performance of bacterial artificial chromosomes-on-beads assays in chromosome analysis of clinical prenatal samples, products of conception and blood samples.
• A child with multiple congenital anomalies due to partial trisomy 7q22.1 → qter resulting from a maternally inherited balanced translocation: a case report and review of literature.
• Distinct roles of ATM and ATR in the regulation of ARP8 phosphorylation to prevent chromosome translocations.
• Heterogeneous MYCN amplification in neuroblastoma: a SIOP Europe Neuroblastoma Study.
• Immense random colocalization, revealed by automated high content image cytometry, seriously questions FISH as gold standard for detecting EML4-ALK fusion.
• Fluorescence in situ hybridisation assays designed for del(7q) detection uncover more complex rearrangements in myeloid leukaemia cell lines
• Detection of t(7;12)(q36;p13) in paediatric leukaemia using dual colour fluorescence in situ hybridisation.
• A rare case of t(11;22) in a mantle cell lymphoma like B-cell neoplasiaresulting in a fusion of IGL and CCND1: case report.
• Genomic DNA-chip hybridization in t(11;14)-positive mantle cell lymphomas shows a high frequency of aberrations and allows a refined characterization of consensus regions.