Lymphoid neoplasms (LNs), including non-Hodgkin's lymphoma (NHL), Hodgkin's lymphoma (HL), lymphoproliferative syndrome (LPS) and multiple myeloma (MM), are among the most frequent cancers ( 17,000 new cases per year in France), after those related to smoking. LNs were investigated using the data from the ENGELA study. ENGELA is a multicenter hospitalbased case-control study that was carried out in France over the period September 2000-December 2004. In all, 822 cases (397 NHL, 149 LH, 168 SLP and 108 MM) and 752 controls were included and described 5,481 and 5,188 first-degree relatives, respectively. A positive association with a familial history of hematopoietic cancer was observed for LN (OR 5 1. were stronger for men. The associations were also stronger when the disease had been diagnosed before the relatives were aged 45 years. The results mainly support the involvement of genetic factors and suggest that at least some of those factors may be sex-linked. However, the slight overrepresentation of affected spouses among the cases might also support the responsibility of environmental factors. ' 2008 Wiley-Liss, Inc.Key words: epidemiology; lymphoid neoplasm; family; aetiology Lymphoid neoplasm (LN), including Hodgkin's lymphoma (HL), non-Hodgkin's lymphoma (NHL), multiple myeloma (MM) and lymphoproliferative syndromes (LPS), are among the most common cancers in France after smoking-related cancers. According to data from French registries, there were 17,000 new cases of LN in 2000 and almost 9,000 deaths. 1 In the last 2 decades , the yearly incidence rate for NHL has increased by more than 3% (3.8% for men and 3.5% for women), for reasons that have yet to be elucidated. 1 A few risk factors for LNs have been identified. They include congenital and acquired immunodeficiencies, 2-5 chromosomal instability syndromes, 6,7 Epstein-Barr virus (EBV) infection [8][9][10] for some Burkitt's 10,11 and HLs, Helicobacter pylori infection for gastric lymphoma 12,13 and some autoimmune disorders for nonHodgkin lymphoma. 14-17 Farming and exposure to pesticides [18][19][20] have also been consistently associated with LN.Several studies have investigated the relationships between familial hematopoietic cancer aggregation and hematopoietic cancer and suggest a 2-fold increase in the risk of NHL [21][22][23][24] and HL 25 with a history of NHL in first-degree relatives.This study analyzed the association between LN and familial history of cancer in the first-degree relatives of the subjects included in a large case-control study designed to investigate for environmental and genetic risk factors for LN.
Material and methodsThe ENGELA study is a French multicenter hospital-based case-control study that was conducted in the main hospitals of Bordeaux, Brest, Caen, Nantes, Lille and Toulouse from September 2000 to December 2004 to investigate for environmental, infectious and genetics risk factors for LN. The LN types considered in the study were LPS, which included chronic lymphoid leukemia (CLL) and hairy cell leukemia (HCL),...