Influence of familial cancer history on lymphoid neoplasms risk validated in the large European case-control study epilymph.

Lymphomas have a potentially important familial component; large studies using recent classification systems are lacking. Based on a multicentre case-control study in seven European countries, we recruited 2480 cases of lymphoid neoplasms (LN) and 2540 controls, matched by country, age and sex. Diagnoses were established according to the World Health Organisation (WHO) classification. We estimated odds ratios (OR) and 95% confidence intervals (CI) for cancer in first-degree relatives and for the kind of relative affected. The OR of LN for a family history of haematological cancer was 1.6 (OR=1.2-2.1). The OR was particularly high for chronic lymphocytic leukaemia (CLL) (OR=2.9 [1.9-4.5]). A familial case of lymphoma increased the risk of Hodgkin's lymphoma (HL) (OR=3.4 [1.5-7.8]). No increased risk was observed for diffuse large B-cell and follicular lymphomas. For CLL and HL, the risk was similar in parents, offspring and siblings. Our study suggests familial aggregation of CLL with a family history of haematological cancer and of HL with a family history of lymphoma. The transmission pattern suggests a dominant model of heredity.