DNA sequencing was performed on 256 patients with available tumor samples to detect genetic aberrations. Genomic DNA was extracted from frozen tumor tissue by a QIAamp DNA Mini Kit (Qiagen, Hilden, Germany) or from formalin‐fixed paraffin‐embedded (FFPE) tumor tissue by a GeneRead DNA FFPE Tissue Kit (Qiagen), based on the manufacturer's guidelines. Whole exome sequencing (WES) data from 44 patients and whole genome sequencing (WGS) data from 9 patients have been reported in our previous manuscript about extranodal DLBCL [20 (link)]. Two hundred and three patients with FFPE tumor tissue or frozen tumor tissue were analyzed by targeted sequencing of 55 lymphoma‐associated genes using the methods defined in the supporting information of our previous study [20 (link)]. Sequencing data have been deposited on https://www.biosino.org/node in project OEP001143.