The 13q14.2-q14.3 probe, labelled in red, covers the D13S319 and D13S25 markers. The 13qter subtelomere specific probe (clone 163C9), labelled in green, allows identification of chromosome 13 and acts as a control probe.
Chromosome 13q abnormalities occur in 16-40% of multiple myeloma cases and are associated with poor prognosis1,2. A case study has shown that in 90% of patients, the 13q14 region was affected and 68% also showed involvement of the 13q21 region – the critical region in all but 8 patients was narrowed down to 13q143. Deletions affecting 13q14 are also the most frequent structural genetic abnormalities in B-cell Chronic Lymphocytic Leukaemia (B-CLL)4. This region is found to be heterozygously deleted in 30-60% and homozygously deleted in 10-20% of CLL patients5. Recently though, the survival rate has been shown to be similar for the two groups6. Two non-coding RNA genes, DLEU1 and DLEU2, and the genetic marker D13S319, span the pathogenic critical region of 13q147. DLEU1 is considered to be the most likely CLL-associated candidate tumour suppressor gene within the 13q14 region8. Subsequently, D13S319, located between the RB1 gene and D13S25 and within the DLEU1 locus, was found to be deleted in 44% of CLL cases9. It has also been postulated that a gene telomeric to the D13S319 region, encompassing D13S25, may be important in cases with hemizygous deletions and that this gene is a putative tumour suppressor gene10.
I first came across CytoCell FISH probes in a previous lab I worked in and I was struck by the quality of the products. Since this time, I have been recommending and introducing CytoCell probes across all application areas — now they are the primary FISH probes used in our lab. They have an excellent range of products and their ready-to-use reagent format saves considerable time.
Medical Technologist, University of Arizona Health Network, USA