SMZL is associated with a number of molecular characteristics, including recurring genomic abnormalities which include del(7q) (approximately 40% cases), KLF2 (20–30%), NOTCH2 (10–25%), TP53 mutations (10–15%), biased IGHV (immunoglobulin heavy variable) gene repertoire with usage of IGHV1-2*04 in 30% of cases, as well as key transcriptomic and epigenetic features of the tumour cells. This evidence concerns the gene NOTCH2 and neoplasm.