XL DLEU/TP53 consists of an orange-labeled probe hybridizing to the DLEU1/MIR15A/MIR16-1 gene region at 13q14.2 including D13S319 and a green-labeled probe hybridizing to the TP53 gene region at 17p13.

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.

The prognosis and clinical course of chronic lymphocytic leukemia (CLL) are heterogeneous. Conventional banding techniques in CLL are hampered by the low mitotic index of the neoplastic cells. The introduction of interphase cytogenetics using fluorescent in situ hybridization (FISH) has greatly increased the sensitivity of cytogenetic analyses. With FISH, abnormalities can be detected in more than 80% of patients by using a 4-probe panel for the detection of trisomy 12q13-15 and deletions 13q14, 17p13, and 11q22-23. An additional 10% of patients can be shown to carry a 6q21 deletion, 14q32 translocation, and partial trisomy 3q or 8q.

TP53 is a tumor suppressor gene which stops cell division when DNA damage is present. Loss of TP53 at 17p13 is a powerful predictor of resistance to therapy with purine analogues and alkylating agents and poor prognosis in CLL. The most frequently deleted region in B-CLL is located in 13q14.3 distal to RB1. The minimal deleted region (MDR) is 350kb in size and includes the gene loci for the mi-RNAs 15 and 16. CLL with 13q deletion as the sole cytogenetic abnormality (del13q-only) usually have a good prognosis.

Clinical Applications

• Chronic Lymphocytic Leukemia (CLL)
• Multiple Myeloma and Plasma Cell Neoplasms (MM)

XL DLEU/TP53 hybridized to bone marrow cells. A cell with normal signal pattern together with cells with a deletion of TP53 (2 orange, 1 green) and cells with deletions of TP53 and DLEU (1 orange, 1 green) are shown.

• Doehner et al (2000) N Engl J Med 343:1910-1916
• Stilgenbauer et al (2002) Leukemia 16:993-1007
• Gunn et al (2008) J Mol Diagn 10:442-451