Letters to the Editor

to a mean relative expression of 40±28 (±SD) in other lymphoma cases (p<0.001, Mann-Whitney U-test). Furthermore, we obtained high expression of one of the Notch2 target genes HES1 with a mean relative mRNA expression of Hes1 of 1.1±1.0 (±SD) in MZL compared to a mean relative expression of 0.34±0.30 (±SD) in other lymphoma cases (p<0.001, Mann-Whitney U-test). These data are in agreement with the importance of Notch2 for marginal zone B-cell differentiation.8-10 Interestingly, the level of NOTCH2 mRNA expression was not higher in the 2 MZL cases with mutations compared to MZL lym-phoma cases without mutations. In conclusion, we iden-tified potentially activating mutations of NOTCH2 in 5% of MZL cases, comprising a splenic and an extranodal MZL case. Additional studies are needed to clarify how these mutations affect Notch signaling and oncogenesis in these lymphomas