PTPN6 and diffuse large B-cell lymphoma: Previous studies have also shown that SHP-1 expression in DLBCL is controlled by DNA methylation and histone acetylation at the SHP-1 P2 promoter which comprises known binding sites for the transcription factors NF-κB [38], Sp1 [39], Oct-1 [39] and PU.1 [65].