Alterations of CHEK2 forkhead-associated domain increase the risk of Hodgkin lymphoma

Checkpoint kinase 2 gene (CHEK2) codes for an important mediator of DNA damage response pathway. Mutations in the CHEK2 gene increase the risk of several cancer types, however, their role in Hodgkin lymphoma (HL) has not been studied so far. The most frequent CHEK2 alterations (including c.470T>C; p.I157T) cluster into the forkhead-associated (FHA) domain-coding region of the CHEK2 gene. We performed mutation analysis of the CHEK2 gene segment coding for FHA domain using denaturing high-performance liquid chromatography in 298 HL patients and analyzed the impact of characterized CHEK2 gene variants on the risk of HL development and progression-free survival (PFS). The overall frequency of CHEK2 alterations was significantly higher in HL patients (17/298; 5.7%) compared to the previously analyzed non-cancer controls (19/683; 2.8%; p= 0.04). Presence of any alteration within the analyzed region of the CHEK2 gene was associated with increased risk of HL development (OR = 2.11; 95% CI = 1.08 - 4.13; p= 0.04). The most frequent I157T mutation was found in 4.0% of HL patients and 2.5% of controls (p = 0.22), however, the frequency of 5 other alterations (excluding I157T) was significantly higher in HL cases and associated with increased risk of HL development (OR = 5.81; 95% CI = 1.12 - 30.12; p= 0.03). PFS in HL patients did not differ between CHEK2 mutation carriers and non-carriers. The predominant I157T mutation together with other alterations in its proximity represent moderate genetic predisposition factor increasing the risk of HL development.

Prognostic impact of bone involvement in Hodgkin lymphoma

The purpose of the study is to determine incidence and prognostic impact of osseous Hodgkin lymphoma (HL). Between 1997 and 2004, 198 patients with HL were treated at our institution. Advanced stages and nodular sclerosis histology prevailed. All patients were treated according to protocols of the German Hodgkin Study Group (GHSG). After minimum follow-up of 24 months, we retrospectively analyzed the incidence of osseous HL, treatment response and parameters of survival. We recorded 14 cases of osseous HL (7 %), always with concurrent nodal disease. Axial skeleton was most frequently involved. Eleven patients (78,5 %) achieved complete remission and three (21,5 %) progressed primarily. The patients with osseous HL had significantly lower 2-year freedom from treatment failure than the patients without bone involvement (71,4 and 92,7 %, respectively, p=0,004), with no significant difference in 2-year overall survival (85,7 and 95 %, respectively, p=0,14). On multivariate analysis, advanced stage was the only independent adverse prognostic factor. In conclusion, bone involvement is a relatively common finding in HL and is not an independent adverse prognostic factor.