CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) is the most common hematologic neoplasm in Western countries and results in the progressive accumulation of CD5(+) CD23(+) B lymphocytes that appear morphologically mature but are functionally incompetent in bone marrow, blood, spleen and lymph nodes of the affected person. Chromosomal translocations are rare events in B-CLL, whereas copy number changes of certain chromosomal regions are frequent, and some of these have been found to be highly prognostic markers of this disease.
The P037 and P038 probemixes contain probes for chromosomal regions and genes that have recurrent copy number aberrations in B-cell CLL: 2p (MYCN, ALK, REL), 6q, 8p (TNFRSF10A/B), 8q (EIF3H, MYC), 9p21 (CDKN2A/B), 10q (PTEN), 11q (ATM, RDX, PPP2R1B, CADM1), chromosome 12, 13q14 (RB1, DLEU1/2/7, KCNRG, MIR15A), 14q, 17p (TP53) and chromosome 19. Moreover, the P038 probemix contains three probes for detection of the NOTCH1 7541-7542delCT, SF3B1 K700E and MYD88 L265P mutations. In addition, 26 reference probes have been included in these two probemixes, detecting several different autosomal chromosomal locations which are relatively quiet in CLL. However, it should be noticed that CLL karyotypes can harbour multiple numerical and structural aberrations, which can complicate interpretation of these reference probes. For further information on genes included in these probemixes see Table 3a and Table 3b.
SD009 Sample DNA
Please note that the mutation-specific probes have only been tested on control plasmids and not on positive human DNA samples with the NOTCH1 7541-7542delCT, SF3B1 K700E and MYD88 L265P mutations! This SD009 sample DNA is provided with each probemix vial and can be used in data binning in the fragment analysis and as a positive control for the mutation-specific probes (see next page).
This SALSA® MLPA® probemix is designed to detect copy number changes, amplifications and/or deletions of one or more sequences in the above mentioned genes and/or chromosomal regions, as well as identify the presence of the aforementioned mentioned mutations in a DNA sample. Heterozygous deletions of recognition sequences should give a 35-50% reduced relative peak height of the amplification product of that probe. Note that a mutation or polymorphism in the sequence detected by a probe can also cause a reduction in relative peak height, even when not located exactly on the ligation site! In addition, some probe signals are more sensitive to sample purity and small changes in experimental conditions. Therefore, deletions and duplications detected by MLPA should always be confirmed by other methods. Not all deletions and duplications detected by MLPA will be pathogenic; users should always verify the latest scientific literature when interpreting their findings.