Expression of STAT6 and Phosphorylated STAT6 in Primary Central Nervous System Lymphomas

5-Hydroxymethylation alterations in cell-free DNA reflect molecular distinctions of diffuse large B cell lymphoma at different primary sites

Background

5-Hydroxymethylcytosine (5hmC), an important DNA epigenetic modification, plays a vital role in tumorigenesis, progression and prognosis in many cancers. Diffuse large B cell lymphoma (DLBCL) can involve almost any organ, but the prognosis of patients with DLBCL at different primary sites varies greatly. Previous studies have shown that 5hmC displays a tissue-specific atlas, but its role in DLBCLs at different primary sites remains unknown.

Results

We found that primary gastric DLBCL (PG-DLBCL) and lymph node-involved DLBCL (LN-DLBCL) patients had a favorable prognosis, while primary central nervous system DLBCL (PCNS-DLBCL) patients faced the worst prognosis, followed by primary testicular DLBCL (PT-DLBCL) and primary intestinal DLBCL (PI-DLBCL) patients. Thus, we used hmC-CATCH, a bisulfite-free and cost-effective 5hmC detection technology, to first generate the 5hmC profiles from plasma cell-free DNA (cfDNA) of DLBCL patients at these five different primary sites. Specifically, we found robust cancer-associated features that could be used to distinguish healthy individuals from DLBCL patients and distinguish among different primary sites. Through functional enrichment analysis of the differentially 5hmC-enriched genes, almost all DLBCL patients were enriched in tumor-related pathways, and DLBCL patients at different primary sites had unique characteristics. Moreover, 5hmC-based biomarkers can also highly reflect clinical features.

Conclusions

Collectively, we revealed the primary site differential 5hmC regions of DLBCL at different primary sites. This new strategy may help develop minimally invasive and effective methods to diagnose and determine the primary sites of DLBCL.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13148-022-01344-1.

Primary central nervous system lymphomas express immunohistochemical factors of autophagy

Primary central nervous system lymphoma (PCNSL) is an aggressive and rare disease. Autophagy is a catabolic mechanism boosting various tumors, including lymphomas; its inhibition is thus a promising therapeutic target. Its presence has never been studied in PCNSLs. We conducted a retrospective immunohistochemical study of 25 PCNSLs for LC3B, p62, and M6PR, comparing it with clinicopathological characteristics. Fourteen (56%) and eleven (44%) PCNSLs were of low and high LC3B expression, respectively. p62 expression was present in most tumors (n = 21, 84%). M6PR was present in all tumors, with 14 (56%) and 11 (44%) cases being of low and high M6PR expression, respectively. LC3B expression was correlated with the performance status (PS) (p = 0.04). No association was found with other clinical parameters, such as deep structure invasion, multiple lesions, complete response, and recurrence after response. p62 showed a strong positive association with MUM1 expression (p = 0.0005). M6PR expression showed a positive correlation (p = 0.04) with PD-L1 expression. No association was found with p53, Ki67, CD8, BCL2, BCL6, or double MYC/BLC2 co-expressors. No association of LC3B, p62, and M6PR expression with survival was found. Our findings provide evidence for the possible presence of autophagic markers in PCNSLs and, thus, for possible treatment targets.