Mutated JAK kinases and deregulated STAT activity are potential therapeutic targets in cutaneous T-cell lymphomaThe malignant mechanisms that control the development of cutaneous T-cell lymphoma (CTCL) are starting to be identified. Recent evidence suggests that disturbances in specific intracellular signaling pathways, such as RAS-MAPK, TCR-PLCG1-NFAT and JAK-STAT, can play an essential role in the pathogenesis of CTCL.1,2 Our group previously reported a network of somatic mutations affecting genes with potential to affect critical Tcell signaling pathways in CTCL patients. 1 As part of our findings we detected a number of mutations potentially affecting JAK/STAT signaling. These findings were recently confirmed by an independent group, suggesting that mutations in this pathway may contribute as disease mechanisms in CTCL.3 Deregulated JAK/STAT signaling is involved in many types of cancer. In fact, somatically acquired genetic alterations of JAK or STAT genes that induce aberrant activation of downstream signaling, via STAT phosphorylation, have been reported in some human hematologic malignancies including T-cell lymphomas. 4,5 We decided to explore JAK/STAT signaling as part of an intricate network of malignant signaling that controls the pathogenesis of CTCL, on the basis of the following evidence: (i) we had detected mutations in the pseudokinase domain of JAK1 and JAK3 in two of 11 patients and one cell line; (ii) we had also found several mutations that can directly (i.e., IL6S/T) or indirectly (i.e., TRAF6, RELB and CARD11) activate JAK/STAT signaling; and (iii) activated STAT3 had been detected in a large proportion of patients with advanced CTCL. 6,7 To explore the mutational status of JAK genes in a larger cohort of human CTCL patients' samples and cell lines, two independent state-of-the-art ultrasequencing approaches were used: a targeted gene-enrichment kit (HaloPlex) coupled to Ion-PGM (Life Technologies) sequencing, and a specific polymerase chain reactionbased amplification protocol targeting the pseudokinase domains of JAK1, JAK2 and JAK3 genes (hereafter, referred to as PsTKd-PCR), followed by specific indexing and sequencing with MiSeq (Illumina; see the Online Supplementary Methods for details). These are two highly sensitive methods that can enable the detection of mutations even present at low frequencies in neoplastic cells or in minority clones which may be found in CTCL samples. Thus, taken together, the data from our series (including those already described by Vaqué et al. © F e r r a t a S t o r t i F o u n d a t i o nthe pseudokinase domain of JAK proteins, a finding that is consistent with the results of other research groups that have found somatic mutations in the same domain of JAK1 and JAK3 kinases in prolymphocytic leukemia, other T-cell leukemias including CTCL and various human malignancies. 3,4,[8][9][10] Thus, it has been shown that JAK pseudokinase domains are auto-inhibitory and keep the kinase domain inactive until receptor dimerization stimulates transition to an a...

Primary cutaneous CD30-positive T-cell lymphoproliferative disorders are the second most common subgroup of cutaneous T-cell lymphomas. They include two clinically different entities with some overlapping features and borderline cases: lymphomatoid papulosis and primary cutaneous anaplastic large cell lymphoma. Molecular studies of primary cutaneous anaplastic large cell lymphoma reveal an increasing level of heterogeneity that is associated with histological and immunophenotypic features of the cases and their response to specific therapies. Here, we review the most significant genetic, epigenetic and molecular alterations described to date in primary cutaneous CD30-positive T-cell lymphoproliferative disorders, and their potential as therapeutic targets.

Our findings suggest that the presence of 6p25.3 rearrangement might be related to this particular biphasic pattern.

DUSP22-rearranged anaplastic lymphomas are characterized by specific morphological features and a lack of cytotoxic and JAK/STAT surrogate markers ALK-negative anaplastic large cell lymphoma (ALKnegative ALCL) is a heterogeneous disease with very disparate outcomes. Molecular studies have identified chromosomal rearrangements involving the DUSP22-IRF4 locus on 6p25.3 (DUSP22 rearrangements) as a favorable prognostic factor, associated with complete remission after first treatment thereby suggesting that this subgroup of patients may not gain additional benefit from autologous stem cell transplantation in first remission. [1][2][3] Recognition of these cases is critical, and we therefore aimed to study in greater detail the histological and immunophenotypic features of DUSP22-rearranged ALK-negative ALCLs.After approval by the Institutional Review Board of the Hospital Universitario Marqués de Valdecilla and the Fundación Jiménez Díaz, Spain, we collected 91 cases with a diagnosis of systemic or primary cutaneous ALCL made at the participating institutions. Clinical data were retrieved and cases were reviewed by 3 independent pathologists (AO, SMRP, and MAP) using hematoxylin & eosin stains. Immunohistochemistry was performed using a panel of antibodies against ALK, CD3, CD4, CD8, granzyme B, MUM1, perforin, P-STAT3 (D3A7, 1/400 Cell Signaling), TIA1, P-STAT5, TCR-βF1, P63, STAT3 (Online Supplementary Appendix). Of 91 evaluated cases, 18 were primary cutaneous ALCLs (pcALCLs) and 73 cases were systemic ALCLs (19 were ALK-positive ALCLs). ALK-positive cases were not further considered for the study. Only 31 cases were eligible for further study due to tissue scarcity, including 22 ALK-negative ALCL and 9 pcALCLs. Fluorescence in situ hybridization (FISH) analyses were performed on these cases using an IRF4-DUSP22 (6p25.3) break-apart probe (KBI-10613; Kreatech, Leica, Spain) following standard procedures. 4,5 Cytotoxic markers, pSTAT3, p63 and MUM1 expression were evaluated as described in the Online Supplementary Appendix. Associations of genetic and immunohistochemical subgroups with overall survival (OS) and progression-free survival were assessed using Kaplan-Meier curves. Differences between genetic subgroups in patients' characteristics, tumor phenotype and other clinical factors were assessed using the χ 2 test and Wilcoxon rank-sum test, as appropriate.

Genomic profiling studies have provided new insights into the pathogenesis of mature B-cell neoplasms and have identified markers with prognostic impact. Recurrent mutations in tumor-suppressor genes (TP53, BIRC3, ATM), and common signaling pathways, such as the B-cell receptor (CD79A, CD79B, CARD11, TCF3, ID3), Toll-like receptor (MYD88), NOTCH (NOTCH1/2), nuclear factor-κB, and mitogen activated kinase signaling, have been identified in B-cell neoplasms. Chronic lymphocytic leukemia/small lymphocytic lymphoma, diffuse large B-cell lymphoma, follicular lymphoma, mantle cell lymphoma, Burkitt lymphoma, Waldenström macroglobulinemia, hairy cell leukemia, and marginal zone lymphomas of splenic, nodal, and extranodal types represent examples of B-cell neoplasms in which novel molecular biomarkers have been discovered in recent years. In addition, ongoing retrospective correlative and prospective outcome studies have resulted in an enhanced understanding of the clinical utility of novel biomarkers. This progress is reflected in the 2016 update of the World Health Organization classification of lymphoid neoplasms, which lists as many as 41 mature B-cell neoplasms (including provisional categories). Consequently, molecular genetic studies are increasingly being applied for the clinical workup of many of these neoplasms. In this review, we focus on the diagnostic, prognostic, and/or therapeutic utility of molecular biomarkers in mature B-cell neoplasms.