We studied PARP1 expression in a series of clinical cases of MCL, with the secondary aim to ascertain the relationship between PARP1 expression and DNA repair gene expression (namely ATM and p53) by immunohistochemical methods.
Germ-line mutations in the ataxia-telangiectasia mutated (ATM) and CHK2 genes have been detected in patients with mantle cell lymphoma (MCL), suggesting a potential role of these genes in genetic predisposition to these tumors.
This allowed the identification of a deletion confined to the genomic region of ATM, which, together with intragenic mutations found in the coding sequence, suggests a role of ATM as a tumor suppressor gene in MCL.
A hemizygous ATM deletion was seen in 44% to 88% of the interphase cells in 15 cases (11.1%); four patients had an indolent lymphoma (follicular center cell lymphoma), and 11 patients had an aggressive lymphoma (five mantle-cell lymphomas [MCLs] and six diffuse large-cell lymphomas).
A nonobese diabetic/severe combined immunodeficient (NOD/SCID) murine xenograft model of an ATM mutant MCL cell line demonstrated significantly reduced tumor load and an increased survival of animals after olaparib treatment in vivo.