Loss of heterozygosity of chromosome 11q(ATM) is the most frequent genomic aberration found in parathyroid adenomas. When the MEN1 tumour suppressor gene was cloned and identified as the primary site of causative germline mutations in familial MEN1, somatic mutations of MEN1 in sporadic parathyroid tumours were then sought, with biallelic inactivation of MEN1 occurring in 12–20%.
ATM gene alteration is a frequent event in the pathogenesis of chronic lymphocytic leukaemia (CLL). It occurs as monoallelic loss in the form of 11q23 deletion, with and without mutation in the remaining ATM allele. ATM is a first DNA damage response gene, and biallelic ATM alterations lead to ATM functional loss and chemoresistance.
The introduction of new therapies, such as intensive chemoimmunotherapy and inhibition of B-cell receptor (BCR) signalling, has changed clinical responses for the majority of CLL tumours, including those with 11q deletion. Still, it remains to be determined whether these strategies can prevent clonal evolution of tumours with biallelic ATM alterations. In this review we discuss ATM function and the consequences of its loss during CLL pathogenesis, differences in clinical behaviour of tumours with monoallelic and biallelic ATM alterations
Chromosomal deletions are recurrent abnormalities in leukaemia, implicating the loss of tumour suppressor genes as an essential mechanism in leukemogenesis. Removal of long arms of chromosomes 5 and 7, moreover, predicts for inferior prognosis in acute myeloid leukaemia (AML) and myelodysplastic syndrome (MDS).1,2 More recently, characterised deletions in myeloid malignancies include deletion 9q in AML, three and elimination 20q in myeloproliferative disorder.4 Deletion 11q is a rare cytogenetic abnormality in the myeloid disorders, with a reported prevalence of 0.7% in de novo and secondary AML and MDS in one study.