1 Introduction
Mature aggressive B-cell lymphoma make up to 50 - 60% of all diagnosed Non-Hodgkin lymphoma (NHL) in children and adolescents in Germany.1 The most common subtypes of mature aggressive B-cell lymphoma are Burkitt lymphoma (BL), Burkitt leukemia (B-AL) and diffuse large B-cell lymphoma (DLBCL).2,3Sporadic BL is less often associated with Epstein–Barr virus (EBV) infection compared to the endemic variant and is the most common variant in North America and Europe.3 In Germany, it is most frequent in children aged 4-14 and is primarily diagnosed in boys with a sex ratio of 4.5 to 1.4 With currently available polychemotherapy an overall survival rate of 80–90% can be reached.5,6 However, relapse of patients, which commonly occurs within six months after end of treatment, results in a very poor outcome and is fatal for most of the patients.4,7
The addition of the monoclonal antibody rituximab targeting CD20 on B cells contributed to the increased survival patients with advanced staged disease.5,6,8,9 Although rituximab and its biosimilars are frequently applied in adults, there is still not much known about the mechanisms of action in vivo due to the lack of an adequate animal model.8 Additionally, biomarkers to identify patients responding to rituximab therapy are lacking.10 Therefore, better understanding of the malignancy and further development of therapeutic strategies are urgently needed.
Here, we show that expression of proteins important for tumor defense is altered at day five after rituximab treatment in patients suffering from B-NHL.