A robust response to ODN+IL-15 was positively linked to presence of chromosomal anomalies (trisomy-12 or ataxia telangiectasia mutated anomaly + del13q14) and negatively linked to a very high proportion of CD38(+) cells within the blood-derived B-CLL population.
In this study, we analyzed 149 bone marrow aspirate or peripheral blood specimens from patients diagnosed with B-CLL, evaluated by four different laboratory studies: morphology examination, three- or four-color flow cytometry analysis, conventional cytogenetics, and fluorescence in situ hybridization (FISH) with a dual-color, break-apart IGH@ probe in addition to a B-CLL FISH probe panel for del(11)(q22) ATM, del(13)(q14.3), del(17)(p13) TP53, and +12.
The functional evaluation of ataxia telangiectasia mutated (ATM) and p53 was recently developed in B-cell chronic lymphocytic leukaemia (B-CLL), a disease in which the response to DNA damage is frequently altered.
Since only in a subset of these cases biallelic inactivation of ATM was observed, we sought to identify other disease-associated genes within 11q22-q23 by analysing NPAT (cell-cycle regulation), CUL5 (ubiquitin-dependent apoptosis regulation) and PPP2R1B (component of the cell-cycle and apoptosis regulating PP2A) for point mutations and their expression in B-CLL by single-strand conformation polymorphism/sequence analysis of the transcripts and real-time polymerase chain reaction.
Although the tumor-suppressor gene ATM in the consensus deletion region was found to be biallelically inactivated in about one third of B-CLL cases, in the majority of those who have this deletion, inactivation of the remaining ATM allele was not observed.
B-cell chronic lymphocytic leukemia (B-CLL) is a clinically variable disease where mutations in DNA damage response genes ATM or TP53 affect the response to standard therapeutic agents.
Deletions in ATM gene region have been found in B-cell chronic lymphocytic leukemia (B-CLL) and mantle cell lymphoma (MCL) and have been considered as an independent prognosis factor in these pathologies.
While ATM mutations in mature B cell tumours (B-CLL and MCL) represent a mixture of missense and truncating errors distributed across the whole of the ATM coding sequence, mutations in sporadic T-PLL appear to be predominantly missense, clustering in the region encoding the PI-3 kinase catalytic domain of the protein.
Frequent inactivating mutations of the ATM gene have been reported in patients with rare sporadic T cell prolymphocytic leukaemia (T-PLL), B cell chronic lymphocytic leukaemia (B-CLL), and most recently, mantle cell lymphoma (MCL).
The putative tumor suppressor genes have remained unrevealed until recently, when the ATM gene was found to carry mutations in cases with deletion in B-CLL, MCL and T-PLL.
ATM mutations are also involved in the development of sporadic human cancers such as T-cell prolymphocytic leukemia and B-cell chronic lymphocytic leukemia.
We show that the ATM gene is mutated in a fraction of B-CLLs and that mutations can be present in the germ line of patients, suggesting that ATM heterozygotes may be predisposed to B-CLL.
To investigate a potential pathogenic role of ATM in B-cell tumorigenesis, we performed mutation analysis of ATM in 29 malignant lymphomas of B-cell origin (B-CLL = 27; mantle cell lymphoma, [MCL] = 2).
In five B-CLLs and one MCL with deletion of one ATM allele, a point mutation in the remaining allele was detected, which resulted in aberrant transcript splicing, alteration, or truncation of the protein.