STAT3 and anaplastic large cell lymphoma: In another study, 59% of BI-ALCL cases showed mutations in ≥ one member of the JAK/STAT pathway, including STAT3 (38%), JAK1 (18%), and STAT5B (3%), and in negative regulators of this pathway, such as SOCS3 (6%), SOCS1 (3%), and PTPN1 (3%) [128].