CARD11 Mutations Research Articles

P1261: ALLG LABORATORY SCIENCE STUDY LS21: MOLECULAR CORRELATES OF RESPONSE IN RELAPSED/REFRACTORY MARGINAL ZONE LYMPHOMA (RRMZL) PATIENTS TREATED WITH ZANUBRUTINIB IN THE MAGNOLIA TRIAL

Background: The MAGNOLIA trial demonstrated the safety and efficacy of zanubrutinib, a second generation BTK inhibitor (BTKi), in patients with rrMZL (ORR 68.2%, CR 26%, 15-month PFS 83%). An exploratory analysis of the ibrutinib-treated rrMZL study showed mutations in genes regulating NF-kB signalling pathway: TNFAIP3 (A20) and MYD88 predicted response, whereas KMT2D (MLL2) and CARD11 were associated with primary resistance. The impact of acquired mutations in BTK and PLCg2 which mediate resistance to BTKi in CLL is unknown in MZL. Aims: This Australasian Leukaemia and Lymphoma Group (ALLG) laboratory science correlative study LS21 seeks to determine if the baseline molecular profile by whole exome sequencing (WES) can predict primary resistance to zanubrutinib, and whether the emergence of resistance mutations in circulating tumour DNA (ctDNA) can herald clinical progression. Methods: DNA was extracted from baseline FFPE tumour samples from 18 patients. Longitudinal monitoring to detect the acquisition of resistance mutations was monitored in 7 patients at multiple time points using cell-free DNA (cfDNA) isolated from plasma. NGS libraries were constructed using Agilent XTHS. Unique molecular barcoding was used to facilitate error correction. Agilent WES Ver7 was used for tumour sequencing. A bespoke bait capture of 48 genes set was used for ctDNA and buccal analysis. Sequencing was performed by NovaSeq 6000 (Illumina, SP flow cell, 2x150bp chemistry) and data processing of FASTQ files via in-house bioinformatic pipeline incorporating fgbio (for UMI de-duplexing, Fulcrumgenomics), VarDict for variant calling and CNVkit for copy number analysis. Variant calls in patient samples (identified by VarDict) were manually curated from a predetermined list of 48 candidate genes by inspecting BAM files in Integrative Genomics Viewer (IGV). Mutational analysis was correlated with clinical data and survival analysis calculated using the Kaplan-Meier (log-rank) method. Results: Baseline WES identified mutations in 33/48 (69%), with a median of 5 genes affected per sample (range: 0-8). In patients treated with zanubrutinib (screen failure n=1), NFkB and NOTCH pathway genes were implicated in 13 (73%) and 10 (56%) patients respectively. KMT2D was most affected (n=7) followed by NOTCH1, NOTCH2, TNFAIP3 and MYD88 (all n=4). Patients with either MYD88 or TNFAIP3 mutations had improved median PFS (not reached (NR) vs 11.1 months, p: 0.009, HR: 0.09, 95% CI: 0.02-0.55); patients with KMT2D showed a trend to worse outcomes (PFS: 13.40 months vs NR, p: 0.06, HR 6.5, 95%CI: 1.06-38.76) [Figure 1a-c]. NOTCH mutations did not associate with outcome. CARD11 mutations were not detected. PLCy2 (H244R, L704V) mutations were detected in 2 patients prior to BTKi commencement but neither was associated with primary resistance. Within the ctDNA cohort, 8/14 (57%) mutations detected in tumour samples were present in ctDNA at study entry. Furthermore, ctDNA also harboured mutations not present in tumour WES in 4 patients, likely reflective of tumour heterogeneity. Two patients had persistent MYD88 mutations detectable in ctDNA 15 months after treatment commencement (to sensitivity of AF 0.13%). Acquired resistance mutations, BTK (C515Y/515F) and PLCy2 (R665W/R742P) were detected in 2 patients who progressed on therapy. Image:Summary/Conclusion: Mutations in genes associated with the NFkB pathway present at baseline are predictive of response to zanubrutinib in rrMZL patients. Detection of acquired BTK and PLCy2 mutations on therapy is feasible and may herald clinical disease progression.

P810: BONE MARROW FAILURE IN PATIENTS CARRYING VARIANTS ON CARD11 GENE.

Background: An accurate differential diagnosis in children with Marrow Failure (MF) is crucial for the clinical management of the disease. In addition to the classical congenital MF (cMF), the role of Inborn Errors of Immunity (IEI) have been recently highlighted as potential cause of the disease. CARD11 is a membrane protein acting as a key signaling scaffold which controls the antigen-induced lymphocyte activation during the adaptive immune response (NF-kB, JNK and mTOR pathway). Germline CARD11 mutations can result in gain/loss of function of the protein leading to different phenotypes (SCID, BENTA disease, atopy, CVID). Several heterozygous hypomorphic/dominant negative (DN) variants of CARD11 have demonstrated a loss of protein function, exhibiting high penetrance and variable expressivity. In particular, mutations in the GUK (Guanylate Kinase) domain seem to be involved in modulating the self-inactivating capacity of CARD11. No CARD11 variants have ever been described to be associated with MF. Herein, we report 4 patients with MF carrying variants on the CARD11 gene. Aims: To evaluate the clinical/immunological features and genetic profile of patients with MF carrying CARD11 variants and followed in our Centre. Methods: A restrospective review of clinical, immunological and genetic data was performed from patients’ records. Molecular analysis was conducted using Next-Generation Sequencing (NGS), targeted panels including genes involved in both cMF and IEI, or by Whole Exome Sequencing (WES). Filtering of variants was performed according to Mendelian disease segregation and zigosity (OMIM), in silico prediction of pathogenicity (ACMG criteria in “Varsome”), and minor allele frequency (reported in GnomAD). Results: Four children carrying variants in the CARD11 gene presented with MF as initial sign of the disease (n=2) or with immune cytopenias further evolving into MF (n=2). Their clinical/immunological features, genetic profile, treatment and follow-up are reported in Table1. Lymphocytes subsets analysis revealed a deficiency of B memory, Tregs and an increased of HLADR+ T cells in all patients. Two cases showed elevated CD4-CD8- TCR αβ+ T-cells (“double negatives T-cells”). All patients showed autoimmune stigmata and 2 of them also presented autoimmune hepatitis. No patients responded to first-line treatment. One responded to second-line treatment with Mychofenolate-mofetil (MMF) and periodic infusion of immunoglobulins. The remaining 3 patients underwent hematopoietic stem cell transplantation (SCT) from haploidentical-αβCD19 depleted transplant (n=2) or HLA-identical cousin (n=1) (Table1). Image:Summary/Conclusion: This report highlights novel phenotypic characteristics of patients carrying variants in CARD11 such as MF and autoimmune hepatitis, thus widening the clinical spectrum of the disease. This underlines the need for an enlarged molecular analysis in pediatric cases of MF and suggests that, in some patients, immune-mediated destruction of blood and marrow cells cooperate in generating the cytopenia. Three variants detected in our cohort are located in the GUK domain of the gene, close to other reported pathogenic dominant negative mutations leading to haploinsufficiency, suggesting interference with the CARD11’s ability to self-inactivate. Functional study will be necessary to confirm the pathogenic role of such variants. Although treatment with MMF may be considered, SCT represents the only curative option for such patients.

Targetable alterations in primary extranodal diffuse large B-cell lymphoma.

Primary extranodal diffuse large B‐cell lymphoma (PE‐DLBCL) is a heterogeneous subgroup of DLBCL. We investigated the prevalence and prognostic value of surface expression of PD‐L1, PD1, and CD30, copy number of 9p24.1 (PD‐L1 region), and mutations in MYD88, CD79B, CARD11, and BTK in a cohort of 116 patients, localized in the mediastinum (PMBL, n = 12), ear, nose and throat (ENT, n = 28), central nervous system (n = 29), testis (n = 7), breast (n = 4), stomach (n = 10), bone (n = 8), spleen (n = 2), and skin (n = 16). PD‐L1 expression is most frequent in PMBL (92%), followed by lymphomas originating in the stomach (57%), ENT (23%), and skin (18%). PD1 was expressed at low levels in less than 13% of PE‐DLBCL, while CD30 expression was found in 58% of PMBL. Mutation analysis revealed an unexpectedly high frequency of MYD88 and CD79B mutations in ENT lymphomas (46% and 50%, respectively). CARD11 mutations are rare but more frequently found in gastric lymphomas (30%), suggesting BTK resistance. Thirty‐four of 113 (30%) of the lymphomas harbored both MYD88 and CD79B mutations. Lower overall and progression‐free survival rates were found for cases with MYD88, CD79B, and BTK mutations. These data confirm the biologic singularity of PE‐DLBCLs and provide some suggestions for targeted therapies.

Primary Cutaneous Mucormycosis, Candida Onychomycosis and Endophthalmitis in a Patient with CARD9 Mutation.

Primary Cutaneous Mucormycosis, Candida Onychomycosis and Endophthalmitis in a Patient with CARD9 Mutation.

Mechanistic impact of oligomer poisoning by dominant-negative CARD11 variants

SummaryThe CARD11 scaffold controls antigen receptor signaling to NF-κB, JNK, and mTOR. Three classes of germline mutations in CARD11 cause Primary Immunodeficiency, including homozygous loss-of-function (LOF) mutations in CARD11 deficiency, heterozygous gain-of-function (GOF) mutations in BENTA disease, and heterozygous dominant-negative LOF mutations in CADINS. Here, we characterize LOF CARD11 mutants with a range of dominant-negative activities to identify the mechanistic properties that cause these variants to exert dominant effects when heterozygous. We find that strong dominant negatives can poison signaling from mixed wild-type:mutant oligomers at two steps in the CARD11 signaling cycle, at the Opening Step and at the Cofactor Association Step. Our findings provide evidence that CARD11 oligomer subunits cooperate in at least two steps during antigen receptor signaling and reveal how different LOF mutations in the same oligomeric signaling hub may cause disease with different inheritance patterns.

Successful Use of Interferon-Gamma for Refractory Disseminated Candida Tropicalis Infection in a Pediatric Patient with Acute Myeloid Leukemia and Heterozygous CARD9 Mutation

Invasive fungal infections remain among the most frequent severe and fatal complications of oncology, despite effective antifungal agents. Genetic aberrations may additionally increase the individual patient’s susceptibility to invasive mycosis, with the need for an intensified treatment, such as adjunctive immunotherapy combined with standard antifungal medication. Interferon-gamma (IFN-γ) as an immunostimulatory agent may represent a promising surrogate to reactivate the cytotoxic activity of macrophages in patients with ‘blind spots’. We report the case of a pediatric patient with AML and disseminated candida tropicalis infection, bearing a heterozygous CARD9 mutation, who was treated successfully with combined IFN-γ and conventional antifungal therapy.

Mismatch Repair Deficiency and Somatic Mutations in Human Sinonasal Tumors.

Simple SummarySinonasal carcinomas are rare tumors with an overall poor prognosis. Due to limitations in local therapeutic approaches, systemic neo-adjuvant or adjuvant therapies are becoming increasingly important in order to improve patient outcome. This study aimed to examine potentially therapeutic targetable molecular alterations in different sinonasal tumors, including deficiency in mismatch repair proteins and microsatellite instability as well as driver mutations. According to our results, immunohistochemical (IHC) analysis of mismatch repair (MMR) proteins and sequencing-based panel analysis should be integrated into the diagnostics of clinically aggressive inverted sinonasal papilloma (ISP) and sinonasal squamous cell carcinoma (SNSCC) in order to enable the therapeutic possibility of a targeted therapy.Due to limitations in local therapy approaches for sinonasal tumors, improvement in systemic therapies plays a pivotal role for prolongation of the patient’s survival. The aim of this study was to examine potential biomarkers, including deficiency in mismatch repair proteins (dMMR)/microsatellite instability (MSI-H) in sinonasal cancers and their precancerous lesions. A comprehensive analysis of 10 sinonasal cancer cell lines by whole exome sequencing, screening 174 sinonasal tumors by immunohistochemistry (IHC) for mismatch repair deficiency and next generation sequencing (NGS) of 136 tumor samples revealed a dMMR/MSI-H sinonasal squamous cell carcinoma (SNSCC) cell line based on a somatic missense mutation in MLH1 and an overall frequency of dMMR/MSI-H SNSCC of 3.2% (4/125). Targetable EGFR mutations were found in 89.3% (25/28) of inverted sinonasal papilloma (ISP) and in 60% (6/10) of ISP-associated carcinomas. While PIK3CA and EGFR mutations were not mutually exclusive, KRAS mutated tumors were an EGFR-wildtype. The effect of potential driver mutations in FGFR2, FGFR3, BRAF, HRAS, MAP2K1, PTEN, NOTCH1 and CARD11 need further investigation. Our results suggest that biomarker testing, including MMR-IHC and NGS panel analysis, should be integrated into the diagnostics of clinically aggressive ISPs and SNSCC to assess prognosis and facilitate therapeutic decisions.

CARD9 Expression Pattern, Gene Dosage, and Immunodeficiency Phenotype Revisited.

CARD9 deficiency is an autosomal recessive primary immunodeficiency underlying increased susceptibility to fungal infection primarily presenting as invasive CNS Candida and/or cutaneous/invasive dermatophyte infections. More recently, a rare heterozygous dominant negative CARD9 variant c.1434 + 1G > C was reported to be protective from inflammatory bowel disease. We studied two siblings carrying homozygous CARD9 variants (c.1434 + 1G > C) and born to heterozygous asymptomatic parents. One sibling was asymptomatic and the other presented with candida esophagitis, upper respiratory infections, hypogammaglobulinemia, and low class-switched memory B cells. The CARD9 c.1434 + 1G > C variant generated two mutant transcripts confirmed by mRNA and protein expression: an out-of-frame c.1358-1434 deletion/ ~ 55kDa protein (CARD9Δex.11) and an in-frame c.1417-1434 deletion/ ~ 61kDa protein (CARD9Δ18 nt.). Neither transcript was able to form a complete/functional CBM complex, which includes TRIM62. Based on the index patient's CVID-like phenotype, CARD9 expression was tested and detected in lymphocytes and monocytes from humans and mice. The functional impact of different CARD9 mutations and gene dosage conditions was evaluated in heterozygous and homozygous c.1434 + 1 G > C members of the index family, and in WT (two WT alleles), haploinsufficiency (one WT, one null allele), and null (two null alleles) individuals. CARD9 gene dosage impacted lymphocyte and monocyte functions including cytokine generation, MAPK activation, T-helper commitment, transcription, plasmablast differentiation, and immunoglobulin production in a differential manner. CARD9 exon 11 integrity is critical to CBM complex function. CARD9 is expressed and affects particular T and B cell functions in a gene dosage-dependent manner, which in turn may contribute to the phenotype of CARD9 deficiency.

Preliminary Safety and Efficacy from a Multicenter, Investigator-Initiated Phase II Study in Untreated TP53 Mutant Mantle Cell Lymphoma with Zanubrutinib, Obinutuzumab, and Venetoclax (BOVen)

Preliminary Safety and Efficacy from a Multicenter, Investigator-Initiated Phase II Study in Untreated TP53 Mutant Mantle Cell Lymphoma with Zanubrutinib, Obinutuzumab, and Venetoclax (BOVen)

AZD4573 Effectively Induces Apoptosis in r/r MCL As a Monotherapy or in Combination with Acalabrutinib

Mantle cell lymphoma (MCL) is an aggressive form of NHL where frequent relapse following standard therapies remains a serious concern, even for promising new treatments such as combinations of a BTK inhibitor with the selective Bcl2 inhibitor venetoclax. Previous studies have also shown that MCL cells develop resistance through tumor microenvironment interactions that increase levels of Mcl1, BclxL, and/or Bfl1. Given the ability of CDK9 inhibition to deplete Mcl1 and Bfl1 (Boiko et al 2021), we explored the potential of clinical-stage inhibitor AZD4573 to induce apoptosis in MCL cell lines and PDX models as a monotherapy or in combination with acalabrutinib. Currently, AZD4573 is being evaluated as a monotherapy in a first-in-human study for relapsed or refractory hematological malignancies (NCT03263637) as well as in combination with the BTK inhibitor, acalabrutinib, in patients with non-Hodgkin lymphoma (NHL) (NCT04630756).CDK9 is a serine/threonine kinase that mediates transcription elongation via phosphorylation of serine 2 of the RNA polymerase II carboxyl-terminal domain (pSer2-RNAP2). As previously shown, potent and selective inhibition of CDK9 by AZD4573 results in reduction of pSer2-RNAP2 levels leading to preferential depletion of labile proteins, including the Bcl2 family anti-apoptotic proteins Mcl1 and Bfl1 (as well as other known oncoproteins like Myc). This in turn drives rapid induction of apoptosis in a broad range of preclinical cancer models, particularly those derived from hematologic malignancies (Cidado et al 2020).Here, we used 7 MCL cell lines and 1 PDX organoid to assess the rapid apoptogenic potential of AZD4573 in vitro. Cleaved caspase-3 (CC3), a hallmark of apoptosis, was measured immediately following acute treatment (6h) using Caspase-Glo 3/7. Four models were sensitive to CDK9 inhibition (EC 50 < 100nM; max. CC3 > 50%) while 1 cell line exhibited intermediate sensitivity (EC 50 < 100nM; max. CC3 < 50%) and 3 others were resistant (EC 50 > 100nM; max. CC3 < 50%). Regardless of sensitivity, AZD4573 caused a dose- and time-dependent reduction of pSer2-RNAP2, Mcl1, and Myc, consistent with our prior reports.Most MCL cell lines are not responsive to BTK inhibition and, therefore, did not show combination benefit with AZD4573. We, therefore, chose to evaluate the in vivo activity of AZD4573 +/- acalabrutinib in 3 disseminated r/r MCL PDX models. In DFBL-44685, an acalabrutinib-unresponsive model harboring a CARD11 mutation, AZD4573 showed moderate activity, reducing MCL cells in all compartments analyzed (peripheral blood, bone marrow, and spleen) by >40% two weeks into treatment and increasing overall survival benefit (P<0.01). In an acalabrutinib-responsive MCL PDX, DFBL-96069, the combination of AZD4573 with acalabrutinib reduced tumor burden in all compartments analyzed by >80% and significantly increased survival over vehicle as well as monotherapy treatments (P<0.001). The third model, DFBL-98848, expresses high Bfl1. In this model, AZD4573 monotherapy reduced disease burden in all compartments analyzed by >50% and significantly increased survival over vehicle (P<0.001). Additionally, AZD4573 plus acalabrutinib further reduced disease burden and increased survival in this model compared to AZD4573 alone, although this did not reach statistical significance.Our findings show that targeting CDK9 with AZD4573 can effectively induce apoptosis in a range of MCL cell lines and PDX models, including acalabrutinib-sensitive and -insensitive models as well as those expressing high levels of Bfl1. In 3 r/r MCL PDX models, single agent AZD4573 significantly reduced the tumor burden in the peripheral blood, bone marrow, and spleen of the affected mice, resulting in increased survival. Combination of AZD4573 with acalabrutinib resulted in greater anti-tumor activity than either monotherapy. Altogether, these data suggest that AZD4573, alone or in combination with acalabrutinib, could be an effective therapy for patients with r/r MCL. [Display omitted] DisclosuresBoiko: AstraZeneca: Current Employment, Current equity holder in publicly-traded company. Andersen: AstraZeneca: Current Employment, Current equity holder in publicly-traded company. Liang: AstraZeneca: Current Employment, Current equity holder in publicly-traded company. Dowdell: AstraZeneca: Current Employment, Current equity holder in publicly-traded company. Reimer: AstraZeneca: Current Employment, Current equity holder in publicly-traded company. Drew: AstraZeneca: Current Employment, Current equity holder in publicly-traded company. Townsley: AstraZeneca: Current Employment, Current equity holder in publicly-traded company. Cidado: AstraZeneca: Current Employment, Current equity holder in publicly-traded company.

Diffuse large B-cell lymphomas in adults with aberrant coexpression of CD10, BCL6, and MUM1 are enriched in IRF4 rearrangements

AbstractDiffuse large B-cell lymphoma (DLBCL) with aberrant coexpression of CD10+BCL6+MUM1+ (DLBCL-AE), classified as germinal center B cell (GCB) type by the Hans algorithm (HA), was genetically characterized. To capture the complexity of DLBCL-AE, we used an integrated approach that included gene expression profiling (GEP), fluorescence in situ hybridization, targeted gene sequencing, and copy number (CN) arrays. According to GEP, 32/54 (59%) cases were classified as GCB-DLBCL, 16/54 (30%) as activated B-cell (ABC) DLBCL, and 6/54 (11%) as unclassifiable. The discrepancy between HA and GEP was 41%. Three genetic subgroups were identified. Group 1 included 13/50 (26%) cases without translocations and mainly showing and ABC/MCD molecular profile. Group 2 comprised 11/50 (22%) cases with IRF4 alterations (DLBCL-IRF4), frequent mutations in IRF4 (82%) and NF-κB pathway genes (MYD88, CARD11, and CD79B), and losses of 17p13.2. Five cases each were classified as GCB- or ABC-type. Group 3 included 26/50 (52%) cases with 1 or several translocations in BCL2/BCL6/MYC/IGH, and GCB/EZB molecular profile predominated. Two cases in this latter group showed complex BCL2/BCL6/IRF4 translocations. DLBCL-IRF4 in adults showed a similar copy number profile and shared recurrent CARD11 and CD79B mutations when compared with LBCL-IRF4 in the pediatric population. However, adult cases showed higher genetic complexity, higher mutational load with frequent MYD88 and KMT2D mutations, and more ABC GEP. IRF4 mutations were identified only in IRF4-rearranged cases, indicating its potential use in the diagnostic setting. In conclusion, DLBCL-AE is genetically heterogeneous and enriched in cases with IRF4 alterations. DLBCL-IRF4 in adults has many similarities to the pediatric counterpart.

The resistance mechanisms and treatment strategies of BTK inhibitors in B-cell lymphoma.

Bruton's tyrosine kinase inhibitors (BTKi) have revolutionized the treatment of B‐cell lymphoma (BCL). These drugs interfere with the mechanisms underlying malignant B‐cell pathophysiology, allowing better drug response as well as low toxicity. However, these multiple mechanisms also lead to drug resistance, which compromised the treatment outcome and needs to be solved urgently. This review focuses on genomic variations (such as BTK and its downstream PCLG2 mutations as well as Del 8p, 2p+, Del 6q/8p, BIRC3, TRAF2, TRAF3, CARD11, MYD88, and CCND1 mutations) and related pathways (such as PI3K/Akt/mTOR, NF‐κB, MAPK signaling pathways, overexpression of B‐cell lymphoma 6, platelet‐derived growth factor, toll‐like receptors, and microenvironment, cancer stem cells, and exosomes) involved in cancer pathophysiology to discuss the mechanisms underlying resistance to BTKi. We have also reviewed the newly reported drug resistance mechanisms and the proposed potential treatment strategies (the next‐generation BTKi, proteolysis‐targeting chimera‐BTK, XMU‐MP‐3, PI3K‐Akt‐mTOR pathway, MYC or LYN kinase inhibitor, and other small‐molecule targeted drugs) to overcome drug resistance. The findings presented in this review lay a strong foundation for further research in this field.

Characterization of molecular genetics and clinicopathology in thymic MALT lymphoma

Extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) lymphoma is a type of low-grade malignant B-cell lymphoma. The aim of this study was to investigate the clinicopathological characteristics of thymic MALT lymphoma. We analyzed the clinical, morphological, immunophenotypical, cytogenetic, and molecular characteristics of 11 cases of thymic MALT lymphoma. The relevant literature was also reviewed. The median age of the 11 patients was 50 (range: 33-60). There was a female predominance with a female-to-male ratio of 10:1. Three patients presented with Sjögren syndrome, autoimmune thrombocytopenia purpura, and type B1 thymoma, respectively. Microscopically, thymic MALT lymphoma was characterized by epithelium-lined cysts that were surrounded by small lymphocytes, centrocyte-like cells, and monocytoid B-cells. Plasmacytic differentiation was observed in two cases. The tumor cells expressed CD20, CD79α, and BCL2. Clonal immunoglobulin genes were detected in all 8 examined cases. Fluorescence in situ hybridization (FISH) for 18q21 was performed in 7 cases, and no translocations involving 18q21 were found. Targeted gene sequencing was performed in five cases with available DNA samples, and TNFAIP3, CARD11, IGLL5, and CCND3 mutations were identified. Thymic MALT lymphoma is a rare type of B cell malignancy with a female predominance and excellent clinical outcomes. Molecular aberrations involving the NF-κB pathway are frequent in thymic MALT lymphoma, suggesting that dysregulation of the NF-κB pathway is an important mechanism underlying the pathogenesis of thymic MALT lymphoma.

Histological and Somatic Mutational Profiles of Mismatch Repair Deficient Endometrial Tumours of Different Aetiologies.

Simple SummaryEndometrial cancers can arise due to an error in DNA mending known as mismatch repair. This can happen because of an error in the cancer itself (somatic) or due to an inherited error (Lynch syndrome). Treatment trials have considered endometrial cancers caused by either of these errors as identical. As it is easier to recruit people with Lynch syndrome, they may be overrepresented in this group despite being less numerous in clinical practice. This would not be an issue if somatic and Lynch syndrome-related endometrial cancers were similar at a molecular level. The data presented herein, however, indicates that these two routes to mismatch repair, although sharing many similarities, lead to endometrial cancers with distinct molecular and pathological features. This may explain the range of outcomes observed in clinical trials of endometrial cancers with mismatch repair errors.Background: Mismatch repair deficient (MMRd) tumours may arise from somatic events acquired during carcinogenesis or in the context of Lynch syndrome (LS), an inherited cancer predisposition condition caused by germline MMR pathogenic variants. Our aim was to explore whether sporadic and hereditary MMRd endometrial cancers (EC) display distinctive tumour biology. Methods: Clinically annotated LS-EC were collected. Histological slide review was performed centrally by two specialist gynaecological pathologists. Mutational analysis was by a bespoke 75- gene next-generation sequencing panel. Comparisons were made with sporadic MMRd EC. Multiple correspondence analysis was used to explore similarities and differences between the cohorts. Results: After exclusions, 135 LS-EC underwent independent histological review, and 64 underwent mutational analysis. Comparisons were made with 59 sporadic MMRd EC. Most tumours were of endometrioid histological subtype (92% LS-EC and 100% sporadic MMRd EC, respectively, p = NS). Sporadic MMRd tumours had significantly fewer tumour infiltrating lymphocytes (p ≤ 0.0001) and showed more squamous/mucinous differentiation than LS-EC (p = 0.04/p = 0.05). PTEN mutations were found in 88% sporadic MMRd and 61% LS-EC, respectively (p < 0.001). Sporadic MMRd tumours had significantly more mutations in PDGFRA, ALK, IDH1, CARD11, CIC, MED12, CCND1, PTPN11, RB1 and KRAS, while LS-EC showed more mutations affecting SMAD4 and ARAF. LS-EC showed a propensity for TGF-β signalling disruption. Cluster analysis found that wild type PTEN associates predominantly with LS-EC, whilst co-occurring mutations in PTEN, PIK3CA and KRAS predict sporadic MMRd EC. Conclusions: Whilst MMRd EC of hereditary and sporadic aetiology may be difficult to distinguish by histology alone, differences in infiltrating immune cell counts and mutational profile may predict heterogenous responses to novel targeted therapies and warrant further study.

Possible Predilections of CARD9 Mutations in Fungal Infections

Possible Predilections of CARD9 Mutations in Fungal Infections

Pathway-Specific Defects in T, B, and NK Cells and Age-Dependent Development of High IgE in Mice Heterozygous for a CADINS-Associated Dominant Negative CARD11 Allele.

CARD11 is a multidomain scaffold protein required for normal activation of NF-κB, JNK, and mTOR during Ag receptor signaling. Germline CARD11 mutations cause at least three types of primary immunodeficiency including CARD11 deficiency, B cell expansion with NF-κB and T cell anergy (BENTA), and CARD11-associated atopy with dominant interference of NF-κB signaling (CADINS). CADINS is uniquely caused by heterozygous loss-of-function CARD11 alleles that act as dominant negatives. CADINS patients present with frequent respiratory and skin infections, asthma, allergies, and atopic dermatitis. However, precisely how a heterozygous dominant negative CARD11 allele leads to the development of this CADINS-specific cluster of symptoms remains poorly understood. To address this, we generated mice expressing the CARD11 R30W allele originally identified in patients. We find that CARD11R30W/+ mice exhibit impaired signaling downstream of CARD11 that leads to defects in T, B, and NK cell function and immunodeficiency. CARD11R30W/+ mice develop elevated serum IgE levels with 50% penetrance that becomes more pronounced with age, but do not develop spontaneous atopic dermatitis. CARD11R30W/+ mice display reduced regulatory T cell numbers, but not the Th2 expansion observed in other mice with diminished CARD11 activity. Interestingly, the presence of mixed CARD11 oligomers in CARD11R30W/+ mice causes more severe signaling defects in T cells than in B cells, and specifically impacts IFN-γ production by NK cells, but not NK cell cytotoxicity. Our findings help explain the high susceptibility of CADINS patients to infection and suggest that the development of high serum IgE is not sufficient to induce overt atopic symptoms.

Genetic Analysis of a Cohort of 275 Patients with Hyper-IgE Syndromes and/or Chronic Mucocutaneous Candidiasis

Hyper-IgE syndromes and chronic mucocutaneous candidiasis constitute rare primary immunodeficiency syndromes with an overlapping clinical phenotype. In recent years, a growing number of underlying genetic defects have been identified. To characterize the underlying genetic defects in a large international cohort of 275 patients, of whom 211 had been clinically diagnosed with hyper-IgE syndrome and 64 with chronic mucocutaneous candidiasis, targeted panel sequencing was performed, relying on Agilent HaloPlex and Illumina MiSeq technologies. The targeted panel sequencing approach allowed us to identify 87 (32 novel and 55 previously described) mutations in 78 patients, which generated a diagnostic success rate of 28.4%. Specifically, mutations in DOCK8 (26 patients), STAT3 (21), STAT1 (15), CARD9 (6), AIRE (3), IL17RA (2), SPINK5 (3), ZNF341 (2), CARMIL2/RLTPR (1), IL12RB1 (1), and WAS (1) have been detected. The most common clinical findings in this cohort were elevated IgE (81.5%), eczema (71.7%), and eosinophilia (62.9%). Regarding infections, 54.7% of patients had a history of radiologically proven pneumonia, and 28.3% have had other serious infections. History of fungal infection was noted in 53% of cases and skin abscesses in 52.9%. Skeletal or dental abnormalities were observed in 46.2% of patients with a characteristic face being the most commonly reported feature (23.1%), followed by retained primary teeth in 18.9% of patients. Targeted panel sequencing provides a cost-effective first-line genetic screening method which allows for the identification of mutations also in patients with atypical clinical presentations and should be routinely implemented in referral centers.

A case of disseminated subcutaneous phaeohyphomycosis caused by Exserohilum rostratum with CARD9 mutation.

Phaeohypomycosis is a rare cutaneous and subcutaneous fungal infection caused by dematiaceous fungi. They have a widespread global distribution occasionally affecting humans. A 26-year-old woman presented with multiple skin lesions over her face and extremities for last 7 years, unresponsive to systemic amphotericin B and itraconazole. Further investigations revealed CARD9 mutation and phaeohyphomycosis caused by the pigmented fungus Exserohilum rosatratum. Lesions subsequently improved with oral flucytosine and itraconazole.

The paracaspase MALT1 in psoriasis.

Psoriasis is a frequent autoimmune-related skin disease, which involves various cell types such as Tcells, keratinocytes and dendritic cells. Genetic variations, such as mutations of CARD14, can promote the development of the disease. CARD14 mutations as well as the stimulation of immune and cytokine receptors activate the paracaspase MALT1, a potent activator of the transcription factors NF-κB and AP-1. The disease-promoting role of MALT1 for psoriasis is mediated by both its protease activity as well as its molecular scaffold function. Here, we review the importance of MALT1-mediated signaling and its therapeutic implications in psoriasis.

Abstract 1267: Combination therapy of JNJ-67856633, a novel, first-in-class MALT1 protease inhibitor, and JNJ-64264681, a novel BTK inhibitor, for the treatment of B-cell lymphomas

Abstract Background: Constitutive activation of the classical nuclear factor kappa-light-chain-enhancer of activated B-cells (NF-κB) pathway is a clear driver of B-cell non-Hodgkin lymphomas (NHL). Bruton's Tyrosine Kinase (BTK) and Mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1), which lies downstream of BTK, are key mediators of the classical NF-κB signaling pathway activated by BCR and TCR receptors. JNJ-67856633 is a first-in-class MALT1 protease inhibitor. JNJ-64264681 is a BTK inhibitor with improved selectivity against BTK. Blocking the BCR pathway at multiple points using these two orally bioavailable compounds could enhance clinical activity in B-cell lymphoma patients. Methods: JNJ-67856633 and JNJ-64264681 are currently being evaluated in phase 1 clinical trials designed to establish safety, PK, PD and the Recommended Phase 2 Dose (RP2D) of each agent. Results: JNJ-67856633 is a potent, selective, orally bioavailable, allosteric inhibitor of MALT1 protease activity. The compound inhibits proliferation of activated B-cell diffuse large B-cell lymphoma (ABC-DLBCL) cell lines bearing CD79b or CARD11 mutations as well as models mimicking resistance to covalent BTK inhibitors. JNJ-67856633 exhibits potent tumor growth inhibition in two human DLBCL xenograft models, OCI-Ly3 and OCI-Ly10, and mutation selected patient derived DLBCL xenografts. Furthermore, treatment with JNJ-67856633 leads to dose dependent inhibition of the generation of Tregs (CD4+CD25+FoxP3+) following CD3/28 stimulation in vitro, suggesting a potential immune modulatory role of MALT1 inhibition. JNJ-64264681 is an orally active small molecule that is a potent, selective, and irreversible covalent BTK inhibitor. JNJ-64264681 inhibits the growth of CD79b-mutant DLBCL cell lines in vitro and potently inhibits tumor growth in xenograft- or patient-derived DLBCL models in vivo. Treatment with JNJ-64264681 and JNJ-67856633 administered together demonstrated statistically significant tumor growth inhibition compared with vehicle control in two CD79b mutant mouse lymphoma models, one based on a DLBCL cell line (OCI-Ly10) and one based on a patient-derived DLBCL model (LY2298). In both models, the combination showed increased growth inhibition compared with single agents and tumor regression in the combination arm. Synergistic anti-proliferative activity was observed in three DLBCL cell lines carrying CD79b mutations and one MCL cell line. Conclusions: Taken together, the in vitro and in vivo data for JNJ-67856633 and JNJ-64264681 suggest that combination therapy can increase the anti-tumor effect of the monotherapies and provide a more sustained response, offering strong support for clinical investigation of the combination of these two novel agents. A phase 1b combination study is scheduled to initiate. Citation Format: Ulrike Philippar, Lorena Fontan, Ivo Cornelissen, Haopeng Rui, Sriram Balasubramanian, Marcello Gaudiano, Mariette Bekkers, Luc Van Nuffel, Tianbao Lu, Tianbao Lu, John Wiener, Mark Tichenor, Tony Greway, Kathryn Packman, Bie Verbist, Yusri Elsayed, Ricardo Attar, Jacqueline Bussolari, John Gerecitano. Combination therapy of JNJ-67856633, a novel, first-in-class MALT1 protease inhibitor, and JNJ-64264681, a novel BTK inhibitor, for the treatment of B-cell lymphomas [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1267.