Anaplastic large cell lymphomas with the 6p25.3 rearrangement are a heterogeneous group of tumours with a diverse molecular background.

ALK-negative anaplastic large cell lymphoma (ALCL) cases with 6p25.3 rearrangement are characterized by peculiar morphological and immunohistochemical features compare to 6p25.3-negative ALK-negative ALCL cases. A subgroup of 6p25.3-positive ALK-negative ALCL cases show the t(6,7) (p25.3;q32.3) rearrangement. Aims: To analyse the differences between 6p25.3-rearranged cases with and without t(6,7) (p25.3;q32.3). Using RNA-sequencing we studied a series of 17 samples showing 6p25.3-rearrangement, identified by FISH, consisting of seven systemic and eight primary cutaneous cases including two examples of secondary skin involvement by systemic ALCL. RNA-sequencing exclusively detected a translocation involving a gene in the 6p25.3 region (either IRF4 or DUSP22) in 7/14 cases (50%). In six of these seven cases the partner proved to be the LINC-PINT region in chromosome 7, while an EXOC2::DUSP22 rearrangement was found in one case. All cases but one were primary cutaneous ALCLs. They all were CD3 positive and BCL2 negative, while most of them expressed p-STAT3. On the contrary, cases without the t(6,7) (p25.3;q32.3) were mainly systemic (71%, 5/7) against just two pcALCL. In general, they lose CD3 (50% positive) and p-STAT3 (25% positive) expression, being all of them BCL2 positive. Moreover, in 60% of them other gene fusions were found. At the transcriptional level, they were characterized by the overexpression of TCF3 (TCF7L1/E2A), DLL3, CD58 and BCL2 genes 75%(6/8) of pcALCL with 6p25.3 rearrangement featured the so-called "biphasic morphologic pattern, which was not found in cutaneous involvement from systemic ALCL. 83% (5/6) of the pcALCL cases with the "biphasic morphologic pattern" showed the t(6,7) (p25.3;q32.3) rearrangement. ALK-negative ALCL cases with 6p25.3 rearrangement are a subgroup of tumours that are heterogeneous with respect to the presence or absence of the t(6,7) (p25.3;q32.3) translocation.

High-throughput RNA sequencing transcriptome analysis of ABC-DLBCL reveals several tumor evasion strategies.

Activated B-cell (ABC) lymphoma, a distinct molecular entity within diffuse large B-cell lymphoma (DLBCL), remains highly incurable, showing a worse response to standard immunochemotherapy. The discouraging results obtained in several clinical trials using proteasome inhibitors, tyrosine kinase inhibitors, or immunomodulators, lead to an intense search for new, potentially druggable biomarkers in DLBCL. In this study, we designed an experimental strategy for DLBCL to discover high- and low-abundance RNA-seq-derived transcripts involved in the oncogenic phenotype in patients diagnosed with ABC-DLBCL. Based on the results of a comparative analysis, 79 DE genes and two enriched gene sets related to metabolism and immunity were selected. Genes related to drug resistance, anti-inflammatory response, and tumor-cell dissemination were found to be up-regulated, while tumor suppressor genes were down-regulated. Then, we searched for the perturbagens most suitable for gene expression profiling (GEP) by iLINCS-CMap. Herein, we present a novel experimental approach that connects the omics signature of DLBCL with potential drugs for more accurate treatments.