PTPN1 and marginal zone lymphoma: Based on recent high‐resolution genomic profiling of 28 GI‐MALT lymphomas (small cell/small cell but with large cell areas/large cell morphology), it appears that in MZL genomic complexity evolves over time, and gains of specific proto‐oncogenes including REL, BCL11A, ETS1, PTPN1, PTEN and KRAS are exclusively found in large cell variants, suggesting these to be involved in a distinct transformation process, while other aberrations are found in all three groups, underlining a clonally‐related origin of lymphoma (Barth et al, 2001; Flossbach et al, 2013).