Development of a mantle cell lymphoma in an ATM heterozygous woman after occupational exposure to ionising radiation and somatic mutation of the second allele

Predisposition to lymphomagenesis is a well-known phenomenon of ataxia-telangiectasia, a recessive disorder caused by germline inactivation of ATM. ATM encodes a protein implicated in the repair of radiation induced double-strand breaks. Biallelic ATM inactivation was described also in sporadic lymphoid malignancies, supporting a role of ATM as a tumour suppressor gene. It is, however, still unclear whether ATM heterozygotes are at higher risk of tumours. We describe an ATM heterozygous patient, who developed a mantle cell lymphoma (MCL) after occupational exposure to ionising radiation and somatic mutation of the second ATM allele supporting the contention that heterozygous germline ATM alterations in combination with irradiation exposure predisposes to sporadic MCL.