Monoallelic and biallelic inactivation of TP53 gene in chronic lymphocytic leukemia: selection, impact on survival, and response to DNA damage.

Authors

MALČÍKOVÁ Jitka ŠMARDOVÁ Jana ROČŇOVÁ Ludmila TICHÝ Boris KUGLÍK Petr VRANOVÁ Vladimíra ČEJKOVÁ Soňa SVITÁKOVÁ Miluše SKUHROVÁ FRANCOVÁ Hana BRYCHTOVÁ Yvona DOUBEK Michael BREJCHA Martin KLABUSAY Martin MAYER Jiří POSPÍŠILOVÁ Šárka TRBUŠEK Martin

Year of publication 2009
Type Article in Periodical
Magazine / Source Blood
MU Faculty or unit

Faculty of Medicine

Citation
Field Oncology and hematology
Keywords chronic lymphocytic leukemia; prognostic marker; TP53; mutation; deletion
Description Deletion of TP53 gene, under routine assessment by fluorescence in situ hybridization analysis, connects with the worst prognosis in chronic lymphocytic leukemia (CLL). The presence of isolated TP53 mutation (without deletion) is associated with reduced survival in CLL patients. It is unclear how these abnormalities are selected and what their mutual proportion is. We used methodologies with similar sensitivity for the detection of deletions (interphase fluorescence in situ hybridization) and mutations (yeast functional analysis) and analyzed a large consecutive series of 400 CLL patients; a subset of p53-wild-type cases (n = 132) was screened repeatedly during disease course. The most common type of TP53 inactivation, ie, mutation accompanied by deletion of the remaining allele, occurred in 42 patients (10.5%). Among additional defects, the frequency of the isolated TP53 mutation (n = 20; 5%) and the combination of 2 or more mutations on separate alleles (n = 5; 1.3%) greatly exceeded the sole deletion (n = 3; 0.8%). Twelve patients manifested defects during repeated investigation; in all circumstances the defects involved mutation and occurred after therapy. Monoallelic defects had a negative impact on survival and impaired in vitro response to fludarabine. Mutation analysis of the TP53 should be performed before each treatment initiation because novel defects may be selected by previous therapies.
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