Histone deacetylase inhibitors (HDACis) are being recognized as a potentially effective treatment approach for peripheral T-cell lymphoma (PTCL), which is a diverse group of aggressive lymphomas with a bleak prognosis. Recent evidence has shown that HDACi are effective in treating PTCL, especially in cases where the disease has relapsed or is resistant to other treatments, and there are few available options. Several clinical trials have demonstrated that HDACi, such as romidepsin and belinostat, can elicit long-lasting positive outcomes in individuals with PTCL, either when used alone or in conjunction with conventional chemotherapy. They exert their anti-tumor actions by regulating gene expression through inhibiting histone deacetylases, which results in the halting of cell division, programmed cell death, and the transformation of cancerous T-cell, as indicated by gene expression profile studies. Importantly, besides clinical trials, real-world evidence indicated that the utilization of HDACi presents a significant and beneficial treatment choice for PTCL. However, although HDACi showed potential effectiveness, they couldn’t cure most patients. Therefore, new combination with conventional drugs as well as new targeted agents are under investigation.

Next generation sequencing (NGS) from SARS-CoV-2-positive swabs collected during the last months of 2022 revealed a large deletion between ORF7b and ORF8 (426 nt) in six patients infected with the BA.5.1 Omicron variant. This extensive genome loss removed a large part of these two genes, maintaining in frame the first 22 aminoacids of ORF7b and the last 3 aminoacids of ORF8. Interestingly, the deleted region was flanked by 2 small repeats, likely involved in the formation of a hairpin structure. Similar rearrangements, comparable in size and location to the deletion, were also identified in 15 sequences in the NCBI database. In this group, 7 out of 15 cases from the USA and Switzerland presented both the BA.5.1 variant and the same 426 nuclotides deletion. It is noteworthy that 3 out of 6 cases were detected in patients with immunodeficiency and is conceivable that this clinical condition could promote the replication and selection of these mutations.

The Tumor Microenviroment (TME) is a complex milieu that is increasingly recognized as a key factor in multiple stages of disease progression and responses to therapy as well as escape from immune surveillance. However, the precise contribution of specific immune effector and immune suppressor components of the TME in Burkitt lymphoma (BL) remains poorly understood. In this paper, we applied the computational algorithm CIBERSORT to Gene Expression Profile (GEP) datasets of 40 BL samples to draw a map of immune and stromal components of TME. Furthermore, by VECTRA multispectral immunofluorescence (IF) and multiple immunohistochemistry (IHC), we investigated the TME of an additional series of 40 BL cases and evaluated the possible role of the PD-1/PD-L1 immune checkpoint axis. Our results indicated that M2 polarized macrophages are the most prominent TME component in BL. In addition, we investigated the correlation between PD-L1 and latent membrane protein-2A (LMP2A) expression on tumour cells, highlighting a subgroup of BL cases characterized by a non- canonical latency program of EBV with an activated PD-L1 pathway. In conclusion, our study analysed the TME in BL and identified a tolerogenic immune signature highlighting new potential therapeutic targets.