Genetic profiles of subcutaneous panniculitis-like t-cell lymphoma and clinicopathological impact of havcr2 mutations

Abstract

Recent studies identified germlinemutations inHAVCR2(encodingT-cell immunoglobulinmucin 3) as a genetic factor that predisposes to subcutaneous panniculitis-like T-cell lymphoma (SPTCL). However, the differences between HAVCR2-mutated (HAVCR2MUT) and HAVCR2 wild-type (HAVCR2WT) SPTCLs remainunclear.Anationwide cohort of 53 patientswith SPTCL diagnosed at 8 Korean institutions was established.Whole-exome sequencing and RNA-sequencing were performed on 8 patients in the discovery set. In the validation set, targeted gene sequencing or direct sequencing of HAVCR2 was performed. Of 49 patients with available HAVCR2 status, 25 (51.0%)wereHAVCR2Y82C.HAVCR2Y82Cwas associatedwith younger age (P5.001), development of hemophagocytic lymphohistiocytosis or hemophagocytic lymphohistiocytosis-like systemic illness (P, .001), and short relapse-free survival (RFS) (P5 .023).Mostmutated genes in SPTCLs were involved in immune responses, epigeneticmodifications, and cell signaling.Mutations in UNC13D, PIAS3, and KMT2D weremore frequent in HAVCR2WT SPTCLs. At the gene expression level, HAVCR2Y82C SPTCLs were enriched in genes involved in IL6-JAK-STAT3 signaling and in tumor necrosis factor-a signaling via NF-kB. CCR4 was significantly upregulated in HAVCR2WT SPTCLs both at themessenger RNA level and at the protein level.We established a risk stratification systemfor SPTCL by integrating clinical and histopathological features, including age andHAVCR2mutation status. This risk stratification systemwas strongly associatedwith RFS (P5 .031). In conclusion, the HAVCR2Y82Cmutationwas common inKoreanpatientswithSPTCL and was associated with unique clinicopathological and genetic features. Combining clinicopathological parameters could aid in predicting prognosis for patients with SPTCL.