Merkel cell carcinoma (MCC) is a highly malignant neuroendocrine tumor of the skin whose molecular pathogenesis is not completely understood, despite the role that Merkel cell polyomavirus can play in 55-90% of cases. To study potential mechanisms driving this disease in clinically characterized cases, we searched for somatic mutations using whole-exome sequencing, and extrapolated our findings to study functional biomarkers reporting on the activity of the mutated pathways. Confirming previous results, Merkel cell polyomavirus-negative tumors had higher mutational loads with UV signatures and more frequent mutations in TP53 and RB compared with their Merkel cell polyomavirus-positive counterparts. Despite important genetic differences, the two Merkel cell carcinoma etiologies both exhibited nuclear accumulation of oncogenic transcription factors such as NFAT or nuclear factor of activated T cells (NFAT), P-CREB, and P-STAT3, indicating commonly deregulated pathogenic mechanisms with the potential to serve as targets for therapy. A multivariable analysis identified phosphorylated CRE-binding protein as an independent survival factor with respect to clinical variables and Merkel cell polyomavirus status in our cohort of Merkel cell carcinoma patients.

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...

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MYD88 L265P is a somatic mutation that has been identified in about 90% of Waldenström macroglobulinemia/lymphoplasmacytic lymphomas (LPLs). It has also been detected in a subset of marginal zone lymphoma (MZL) cases, but the frequency and clinical and histologic features of these mutated MZL cases has only been partially characterized. We have developed a customized TaqMan allele-specific polymerase chain reaction for sensitive detection of this mutation in paraffin-embedded tissue. We analyzed samples from 19 patients with LPL, 88 patients with splenic marginal zone lymphoma (SMZL), 8 patients with nodal marginal zone lymphoma (NMZL), 21 patients with extranodal mucosa-associated lymphoid tissue (MALT), and 2 patients with B-cell lymphoma not otherwise specified. By integrating mutational, histologic, and clinical data, 5 cases were reclassified as LPL. After reclassification, MYD88 L265P was detected in 13/86 (15%) SMZL and in 19/24 LPL (79%) cases. The mutation was absent from NMZL and MALT cases. A strong correlation was found between the presence of an IgM monoclonal paraproteinemia and the MYD88 L265P mutation (P<0.0001). SMZL cases positive for MYD88 L265P were also associated with monoclonal IgM paraproteinemia (4/13 cases; P<0.0283), although with less serum paraproteinemia. They also had a higher frequency of plasmacytic differentiation (9/13) but with no correlation between the presence of mutation and of light chain-restricted plasma cells in tissue. Demonstration of the MYD88 L265 mutation is a valuable tool for the diagnosis of LPL, although some SMZL cases carrying the mutation do not fulfill the diagnostic criteria for LPL.

The simplicity and low cost of rapid point-of-care tests greatly facilitate large-scale population testing, which can contribute to controlling the spread of the COVID-19 virus. We evaluated the applicability of a self-testing strategy for SARS-CoV2 in a population-based, cross-sectional study in Cantabria, Spain, between April and May 2020. For the self-testing strategy, participants received the necessary material for the self-collection of blood and performance of a rapid antibody test using lateral flow immunoassay at home without the supervision of healthcare personnel. A total of 1,022 participants were enrolled. Most participants correctly performed the COVID-19 self-test the first time (91.3% [95% CI 89.4–92.9]). Only a minority of the participants (0.7%) needed the help of healthcare personnel, while 6.9% required a second kit delivery, for a total valid test result in 96.9% of the participants. Incorrect use of the self-test was not associated with the educational level, age over 65, or housing area. Prevalence of IgG antibodies against SARS-CoV2 for subjects with a valid rapid test result was 3.1% (95% CI 2.2–4.4), similar to the seroprevalence result obtained using a conventional approach carried out by healthcare professionals. In conclusion, COVID-19 self-testing should be considered as a screening tool.