NOTCH2 expression in SMZL. Western blot analysis of NOTCH2 protein expression in purified primary tumor cells from 5 SMZL cases carrying WT or mutated (M) NOTCH2, and in the SMZL cell line Karpas 1718, also WT for NOTCH2 (left); the specificity of the antibody was validated by using the BJAB cell line, which lacks NOTCH2 mRNA expression (right; asterisk indicates nonspecific band). Arrow indicates the intact NOTCH2 protein; a band of lower molecular weight, consistent with the predicted size of the NOTCH2 protein encoded by the mutant allele, can be detected in all NOTCH2-mutated patients, but not in NOTCH2 WT samples. Where available, the relative NOTCH2 mRNA levels in the same samples are quantified by qRT-PCR (bottom; na, not available).