Design and standardization of PCR primers and protocols for detection of clonal immunoglobulin and T-cell receptor gene recombinations in suspect lymphoproliferations: report of the BIOMED-2 Concerted Action BMH4-CT98-3936

Immune age is correlated with decreased TCR clonal diversity and antibody response to SARS-CoV-2

Immune response to infection or vaccination is compromised with age. We aimed to examine associations between immune senescence, T and B cell clonal diversity and immunoglobulin G secretion in response to immune challenge in isolated peripheral blood mononuclear cells (PBMC) from people of different chronological ages. We isolated PBMC from 49 individuals categorised into < 35 years and > 60 years age groups. Cells were then challenged with recombinant SARS-CoV-2 spike protein or vehicle and IMMAX score was calculated for each sample from flow cytometry. Antibody response was assessed using the proxy of IgG secretion and T cell receptor and immunoglobulin framework region recombination was determined by clonality studies. We observed that individuals aged > 60 years demonstrated a higher immune 'age' as calculated by IMMAX score (0.75 compared with 0.48 for individuals aged < 35 years; p = < 0.0001). Immune age negatively correlated with IgG responsivity in older individuals with recent prior exposure to SARS-CoV-2 (b = -0.01; p = 0.05). Higher immune age was also negatively correlated with TCR Vd + Jd receptor diversity regardless of immune challenge (b = -0.02; p = < 0.0001 and b = -0.02; r2 = 0.0.35; p = < 0.0001 for control and exposed samples respectively). Our data demonstrate that PBMC samples from older people display a higher cellular immune age and attenuation of immune response. This suggests that future treatments targeting cellular ageing of immune cells may be a useful avenue for investigation to improve immune function in older people.

Presence of minimal residual disease determined by next-generation sequencing is not a reliable prognostic biomarker in children with acute lymphoblastic leukemia

The role of next-generation sequencing (NGS) for minimal residual disease (MRD) assessment in pediatric acute lymphoblastic leukemia (ALL) is still under consideration. Fifty pediatric patients were prospectively evaluated for specific clonal rearrangements of immunoglobulin and T-cell receptor genes using NGS analysis at diagnosis and on days 33 and 78 from therapy onset. The prognostic value or the NGS-MRD status was analyzed after a median follow-up of 4 years. All but one patient with negative NGS-MRD status on day 33 are in clinical remission. A total of 29 (58%) patients were NGS-MRD positive on day 33, of which 9 (18%) patients remained positive on day 78. However, only a small percentage of the patients with positive NGS-MRD status on day 33 and day 78 relapsed: 21% (6/29) and 33% (3/9), respectively. Positive NGS-MRD status is not a reliable prognostic biomarker in children with ALL and warrants careful consideration in disease stratification.

Composite mantle cell lymphoma with cryptic ins(11;2)(q13;p11.2p11.2)/IGK::CCND1 and lymphoplasmacytic lymphoma with MYD88 L265P mutation

A woman in her 80 s presented with generalized lymphadenopathy, bone marrow (BM) involvement, and leukemic manifestation. Lymph node biopsy revealed typical histopathology of mantle cell lymphoma (MCL) and the CD5+ and immunoglobulin μ+δ+/λ+ immunophenotype, with unmutated IGHV. BM was infiltrated with not only MCL but also another B-cell tumor that was CD5- and μbright+δ+/κ+, being consistent with M proteins in the serum and urine, with mutated IGHV. As the latter lymphoma component carried the MYD88 L265P mutation, this case represented a composite of MCL and lymphoplasmacytic lymphoma. Next-generation sequencing revealed a cryptic insertion of IGK enhancer sequences into the CCND1-major translocation cluster, accounting for CCND1 expression in MCL cells recognized by immunohistochemistry. Composite lymphoma is rare, but a correct diagnosis is required because effective treatments for each component are now available.

Diagnosis and Classification of Primary Nodal Lymphomas in Dogs: A Consensus of the Oncology-Pathology Working Group

One of the primary objectives of the Oncology Pathology Working Group (OPWG) is for oncologists and pathologists to collaboratively generate consensus documents to standardise aspects of and provide guidelines for oncologic pathology in veterinary species. Consensus is established through critical review of the peer-reviewed literature relevant to a subgroup's particular focus. In this article, the authors provide a critical review of the current literature regarding methods for the diagnosis and classification of primary nodal lymphomas of dogs, including histopathology, cytopathology, immunophenotyping and assessment of molecular clonality. Knowledge gaps in the current literature and recommendations for future study are also reported. Major conclusions of this consensus include: (1) Histopathology with immunohistochemistry is required for complete diagnosis and classification of nodal lymphomas; (2) Immunohistochemistry and flow cytometry are the most reliable methods of immunophenotyping lymphomas, though neither is clearly superior to the other; (3) Molecular clonality testing should not be used in favour of immunophenotyping assays for classifying lymphomas; and (4) The use of emerging molecular tests for diagnosing lymphomas in the absence of histopathologic, cytopathologic, or immunophenotypic disease characterisation should be restricted to investigational settings until their diagnostic validity and the clinical benefit they confer to patients are more thoroughly characterised. This document represents the opinions of the OPWG and the authors; it does not constitute a formal endorsement by the American College of Veterinary Pathologists or the Veterinary Cancer Society.

Antigen selection reflected in the subclonal architecture of the B-cell receptor immunoglobulin gene repertoire in splenic marginal zone lymphoma

Almost one-third of all splenic marginal zone lymphoma (SMZL) cases express B-cell receptor immunoglobulin (BcR IG) encoded by the IGHV1-2*04 gene, implicating antigen selection in disease ontogeny. Evidence supporting this notion mostly derives from low-throughput sequencing approaches, which have limitations in capturing the full complexity of the BcR IG gene repertoire. This hinders the comprehensive assessment of the subclonal architecture of SMZL as shaped by antigen selection. To address this, we conducted a high-throughput immunogenetic investigation of SMZL aimed at the comprehensive characterization of the somatic hypermutation (SHM) and intraclonal diversification within the IG genes. We identified significant differences in the SHM and ID profiles between cases expressing the IGHV1-2*04 gene and those expressing other IGHV genes. Specifically, IGHV1-2*04 cases displayed (i) targeted SHM resulting in recurrent replacement SHMs, and (ii) significantly more pronounced intraclonal diversification, reflecting ongoing antigen selection. Overall, our findings suggest that SMZL cases expressing the IGHV1-2*04 gene have a distinct immunogenetic signature shaped by microenvironmental pressure on the clonotypic BcR IG, corroborating the idea that this group may represent a distinct molecular variant of SMZL.

A patient-derived T cell lymphoma biorepository uncovers pathogenetic mechanisms and host-related therapeutic vulnerabilities

Peripheral T cell lymphomas (PTCLs) comprise heterogeneous malignancies with limited therapeutic options. To uncover targetable vulnerabilities, we generate a collection of PTCL patient-derived tumor xenografts (PDXs) retaining histomorphology and molecular donor-tumor features over serial xenografting. PDX demonstrates remarkable heterogeneity, complex intratumor architecture, and stepwise trajectories mimicking primary evolutions. Combining functional transcriptional stratification and multiparametric imaging, we identify four distinct PTCL microenvironment subtypes with prognostic value. Mechanistically, we discover a subset of PTCLs expressing Epstein-Barr virus-specific T cell receptors and uncover the capacity of cancer-associated fibroblasts of counteracting treatments. PDXs' pre-clinical testing captures individual vulnerabilities, mirrors donor patients' clinical responses, and defines effective patient-tailored treatments. Ultimately, we assess the efficacy of CD5KO- and CD30- Chimeric Antigen Receptor T Cells (CD5KO-CART and CD30_CART, respectively), demonstrating their therapeutic potential and the synergistic role of immune checkpoint inhibitors for PTCL treatment. This repository represents a resource for discovering and validating intrinsic and extrinsic factors and improving the selection of drugs/combinations and immune-based therapies.

Development and validation of novel models based on clonality immunoglobulin gene rearrangement for evaluation of bone marrow involvement and prognostic prediction in patients with diffuse large B-cell Lymphoma: a multicenter retrospective study

Introduction

Bone marrow involvement (BMI) is a poor prognostic factor in diffuse large B cell lymphoma (DLBCL), and accurate evaluation of BMI is crucial for determining stages and prognosis. This study aimed to identify the most effective examinations for evaluating BMI in DLBCL, including positron emission tomography-computed tomography (PET/CT), immunoglobulin gene rearrangement (IGR), flow cytometry (FCM), bone marrow cytology (BMC) and bone marrow biopsy pathology (BMB), and to further explore its prognostic significance in DLBCL patients.

Methods

This retrospective study included 364 newly diagnosed DLBCL patients, all of whom underwent PET/CT, IGR, FCM, BMC, and BMB at diagnosis. Survival outcomes were analyzed via Kaplan-Meier and Cox regression models. Novel prognostic models incorporating combined IGR and BMB results were developed in a training cohort.

Results

Compared to other detection methods, Clonal IGR BMI-positive were found the highest rate of 114 patients (31.3%), and IGR BM involvement-positive patients of DLBCL had the worst survival outcomes, especially among patients in stages I to III (P<0.001). Notably, PET/CT existed some limitations in BMI diagnosis, particularly in stage IV patients (P>0.05). Additionally, the combination of IGR and BMB demonstrated superior prognostic predictive capability for the patients in stage IV (PP<0.001). Multivariate analysis further confirmed that double-positive BMI of IGR and BMB was an independent prognostic factors of PFS (P=0.026) and OS (P=0.042). In addition, the novel IPI and NCCN-IPI stratification models were established by incorporating the combination of IGR and BMB in training group. The C-index of novel models were increased when IGR and BMB were supplemented in our cohort.

Discussion

Our results suggest that IGR is the most valuable methods for evaluating BMI compared to traditional detection methods. Adding the combination of IGR and BMB to the IPI and NCCN-IPI score may improve their predictive ability. In summary, IGR is essental for evaluation of BMI and provide an ideal method for disease staging and risk stratification in DLBCL patients in the rituximab era.

Hydroa vacciniforme lymphoproliferative disorder, a clinicopathologic and genetic analysis

Hydroa vacciniforme lymphoproliferative disorder (HV-LPD) is a rare Epstein-Barr virus (EBV)-associated disease and the systemic form shows a propensity to progress and some cases may eventually develop a disease simulating NK/T-cell lymphoma or even aggressive NK-cell leukemia. We report 12 patients with systemic HV-LPD of median age 15.8 years with dermatosis involving the face, trunk, extremities and serous membranes. Ten of 12 patients (83 %) had systemic symptoms including 9 with prominent facial edema and 2 with bone marrow involvement. All cases were positive for EBER and CD3 and lacked CD20. Additional positive markers included CD8 in 11 of 12 (91.6 %), CD56 in 1 of 12 (8.3 %), granzyme B in 6 of 7 (85.7 %), TIA1 in 2 of 2 (100 %) and CD30 in 1 of 3 (33.3 %). Two cases studied demonstrated monoclonal TCR-γ and one also had TCR-β rearrangements. Five cases were sequenced and showed recurrent mutations in ALMS1, ALPK2, BCORL1, KANK2, KMT2D, NCOR1, PTPRD, RHOA, TNIK, TP53 and ZFHX3, and single cases showed a variety of mutations including BCOR, CREBBP, DDX3X, DMXL2, IRF4, IRF8, KDM6A, MGA, NCOR2, PLCG1, PRDM1, RNF213, SMARCA4, STAT5B and TET2 mutation. Most patients were treated with immunomodulating therapy, two received methotrexate, three received multiagent chemotherapy and one underwent hematopoietic stem cell transplant. Follow-up was available in 10 patients of whom 6 died of disease and one was alive without disease. Our results showed that patients with persistent/progressive systemic HV-LPD have a poor prognosis and did not respond well to chemotherapy. The mutation spectrum bore some resemblance to extranodal NK/T lymphomas but also had notable differences.

NGS-MRD negativity in post-HSCT ALL spares unnecessary therapeutic interventions triggered by borderline qPCR results without an increase in relapse risk

Monitoring of minimal residual disease (MRD) after hematopoietic stem cell transplantation (HSCT) in patients with acute lymphoblastic leukemia (ALL) is vital for timely therapeutic intervention planning. However, interpreting low-positive results from the current standard method, quantitative PCR (qPCR) of immunoglobulin and T-cell receptor gene rearrangements (IG/TR), poses challenges due to the risk of false positivity caused by non-specific amplification. We aimed to improve MRD detection specificity using the next-generation amplicon sequencing (NGS) of IG/TR rearrangements for better relapse prediction. In pediatric and young adult ALL patients undergoing sequential post-HSCT MRD monitoring, we prospectively re-tested positive non-quantifiable qPCR results with NGS-MRD using the EuroClonality-NGS approach. We were able to confirm 13 out of 47 (27.7%) qPCR positive results using the more specific NGS-MRD method. Out of 10 patients with at least one MRD positivity confirmed by NGS, six relapsed (60%) 1-3.7 months after testing. Among 25 patients with all NGS-MRD results negative, two relapses occurred (8%) after 5.1 and 12.1 months. One-year RFS was 40% versus 96% and 3-year OS was 33.3% versus 94.4% for the NGS-positive and NGS-negative groups, respectively. The difference was not attributable to a varying rate of therapeutic interventions. Six patients out of 14 who had immunosuppressive treatment tapered or received donor lymphocyte infusion in response to MRD positivity developed significant graft versus host disease, leading to one fatality. This underscores the importance of enhancing the post-HSCT relapse risk prediction accuracy through NGS-MRD testing to avoid unnecessary interventions.

Molecular substratification of endometrial carcinomas with no special molecular profile (NSMP) by using a limited NGS custom panel may facilitate effective patient selection for the PIK3CA-targeted therapy

Endometrial carcinomas (EC) of no special molecular profile (NSMP) represent the largest molecular category of EC, comprising a mixture of tumors with different histology and molecular profiles. These facts likely point to different tumor biology, clinical outcomes, and targeted therapy responses within this molecular category. The PIK3CA is currently the only targetable kinase oncoprotein directly implicated in EC carcinogenesis. Investigating a unique single-institution cohort, we attempted to stratify NSMP ECs based on the presence of the PIK3CA pathogenic mutation. Those cases were further analyzed for other well-established-associated oncogenic driver gene mutations. Histological and clinical variables were also correlated in each case. Altogether, 175 ECs were prospectively tested by a limited custom NGS panel containing ARID1A, BCOR, BRCA1, BRCA2, CTNNB1, KRAS, MLH1, MSH2, MSH6, NRAS, PIK3CA, PMS2, POLD1, POLE, PTEN,and TP53 genes. We identified 24 PIK3CA mutated cases in the group of 80 NSMP ECs, with another co-occurring mutation in at least one oncogenic driver gene (CTNNB1, PTEN, ARID1A, KRAS, BCOR, PMS2) in 19 cases. In conclusion, a limited NGS panel can effectively test EC tissue for specific pathogenetically relevant oncogene mutations. The NSMP EC category contains 30% of the PIK3CA mutated cases. Of those, 21% contain the PIK3CA mutation as a sole EC-associated oncogene mutation, while 79% harbor at least one more mutated gene. These findings may inform future healthcare planning and improve the effectiveness of EC patient selection for the PIK3CA-targeted therapy.

Recurrent primary cutaneous marginal zone lymphoma: a comparative study of initial tumours, recurrences, and outcomes in 61 patients

AIMS

Primary cutaneous marginal zone lymphoma (PCMZL) is considered a lymphoproliferative disorder (International Consensus Classification, ICC) or an overt lymphoma (WHO-HAEM5). Seeking evidence for a reactive process or true lymphoma, we retrieved recurrent PCMZLs from the French Study Group of Cutaneous Lymphoma (GFELC) database.

METHODS

Histology, phenotype (light-chain restriction, immunoglobulin, and immune-receptor translocation-associated protein-1 [IRTA1] expression) and B-cell clonality at diagnosis and recurrence were compared according to recurrence site (local, locoregional, or distant) and outcomes.

RESULTS

Initial lesions of the 61 patients (mean age 52) were mostly isolated on the trunk (48%) and classified T1 (70%). Times to first recurrence for local, locoregional, and distant recurrences, were 20, 29, and 37 months, respectively. Light-chain restriction type did not differ significantly between local/locoregional recurrences and distal recurrences (P = 0.06; n = 60). The same B-cell clones were identified for 23/42 local/locoregional recurrences, while 5/19 distant recurrences showed different clonal profiles (P = 0.0003). No tumour expressed IRTA1. Fifty-eight tumours were heavy-chain (IgG/IgG4) class-switched PCMZLs and 3 IgM+/IgD- PCMZLs. All IgM+ tumours underwent either transformation (skin or brain) into diffuse large B-cell lymphomas (DLBCLs) and extracutaneous spreading.

CONCLUSION

As suggested by WHO-HAEM5, immunoglobulin phenotype assessment (IgM alongside IgD) appears to be a possible valuable tool in the initial diagnosis of PCMZL to differentiate between the indolent class-switched PCMZL (IgM-negative) and IgM+ (IgD-) PCMZL, which has an uncertain prognosis. The variation in B-cell rearrangements and light chain restriction observed in distant recurrences of PCMZL may suggest different antigen-driven stimulation processes.

Origins of T-cell-mediated autoimmunity in acquired aplastic anaemia

Acquired aplastic anaemia (AA) is an autoimmune bone marrow failure disease resulting from a cytotoxic T-cell-mediated attack on haematopoietic stem and progenitor cells (HSPCs). Despite significant progress in understanding the T-cell repertoire alterations in AA, identifying specific pathogenic T cells in AA patients has remained elusive, primarily due to the unknown antigenic targets of the autoimmune attack. In this review, we will synthesize findings from several decades of research to critically evaluate the current knowledge on T-cell repertoires in AA. We will highlight new insights gained from recent in vitro studies of candidate autoreactive T cells isolated from AA patients and will discuss efforts to identify shared T-cell clonotypes in AA. Finally, we will discuss emerging evidence on the potential T-cell cross-reactivity between HSPC and common viral epitopes that may contribute to the development of AA in some patients. We conclude by highlighting the areas of consensus and limitations, as well as the ongoing uncertainties, and we identify promising directions for future research in the field.

Preliminary assessment of the accuracy of cutaneous T-cell lymphoma diagnosis through deep sequencing of the TRG gene

BACKGROUND

The diagnostic challenges in early mycosis fungoides (MF) and other cutaneous T-cell lymphomas (CTCLs) persist despite advancements in molecular methods.

OBJECTIVES

To provide a preliminary assessment of next-generation sequencing (NGS) in analysing TRG (T-cell receptor gamma locus) sequences for distinguishing CTCLs from benign inflammatory skin disorders.

METHODS

NGS was used to assess TRG sequences in skin samples from clinicopathologically proven CTCLs and benign inflammatory skin disorders.

RESULTS

Our study analysed skin samples from a total of 36 participants, comprising 22 cases of CTCL, including 14 MF and 8 other CTCLs, alongside 14 cases of benign inflammatory skin disorders. According to LymphoTrack® criteria, monoclonality was detected in 16 (73%) of the 22 patients with CTCL. Specifically, in cases of MF, 10 of 14 (71%) were identified as monoclonal, with all 4 non-monoclonal cases being in the patch stage. For the other cases of CTCL, six of eight displayed monoclonality. Among the 22 patients with CTCL, 10 (45%) had multiple biopsies, with 8 (36%) displaying the same dominant clone across different sites. Among the 14 benign cases, only the case of erythrodermic psoriasis exhibited monoclonality. Our decision tree analysis suggests that a high frequency of the most abundant clone, its ratio to the third most abundant clone and TRG VγI segment usage are effective markers that can help in the diagnosis of CTCL.

CONCLUSIONS

A combination of the clone frequencies and TRG V segment usage may enhance diagnosis of MF and other CTCLs, helping to differentiate them from benign conditions. However, molecular diagnosis for patch-stage MF remains challenging.

Vvax001, a Therapeutic Vaccine, for Patients with HPV16-Positive High-grade Cervical Intraepithelial Neoplasia: A Phase II Trial

PURPOSE

Human papillomavirus (HPV) infection is the major cause of (pre)malignant cervical lesions. We previously demonstrated that Vvax001, a replication-incompetent Semliki Forest virus vaccine encoding HPV type 16 (HPV16) E6 and E7, induced potent anti-E6 and -E7 cytotoxic T-cell responses. In this study, we investigated the clinical efficacy of Vvax001 in patients with HPV16-positive cervical intraepithelial neoplasia (CIN) grade 3 (CIN3).

PATIENTS AND METHODS

Patients with newly diagnosed HPV16-positive CIN3 were eligible for participation. Patients received three immunizations of Vvax001 (5 × 107 infectious particles) at a 3-week interval. Up to 19 weeks after the last immunization, patients were monitored for regression of CIN3 by colposcopy. A colposcopy-guided biopsy was taken at the last visit, and a standard-of-care loop excision was performed only in case of remaining CIN grade 2/CIN3. Histopathologic response rates, HPV16 clearance, treatment-related adverse events, and vaccine-induced immune responses were assessed.

RESULTS

A total of 18 patients were enrolled and fully immunized. Colposcopic examination revealed a reduction in CIN3 lesion sizes in 17/18 (94%) patients already evident from 3 weeks onward after the last immunization. A histopathologic complete response (regression to CIN grade 1 or no dysplasia) was observed in 9/18 patients (50%) and HPV16 clearance in 10/16 patients (63%). Vvax001 did not induce clearance of other HPV types. To date, no recurrences have been observed, with a median and longest disease-free survival of 20 and 30 months, respectively. No serious adverse events were observed.

CONCLUSIONS

Treatment with Vvax001 is safe and feasible and shows preliminary clinical effectiveness in patients with HPV16-associated CIN3 lesions.

T-cell Receptor (TCR)-Vβ Repertoire Flow Cytometry for T-cell Lymphoproliferative Disorder: a Retrospective Analysis of a Single-Center Real-Life Laboratory Experience

Background

Discrimination between clonal and reactive cell proliferation is critical for the correct management of T-cell lymphocytosis. Multiparametric flow cytometry (MFC) represents a valuable tool, particularly because it allows the evaluation of the T-cell receptor (TCR) Vβ repertoire to pinpoint eventual clonality in T-cell lymphocytosis. A restricted expansion of a single out of the 24 evaluable families or a "clonogram-off" pattern is highly suggestive of the presence of a clonal T-cell population. However, data available on the concordance between MFC TCR-Vβ repertoire and molecular analysis of TCR gene rearrangements, which is regarded as the gold standard for assessing T-cell clonality, are limited.

Objective and methods

We performed a retrospective monocentric study involving 307 patients referred to our center for lymphocytosis between 2003 and 2024. The aim of our study was to investigate the diagnostic accuracy of MFC TCR-Vβ repertoire analysis and compare its performance with molecular analysis of TCR gene rearrangements for the identification of T-cell clonality.

Results

In clonally restricted cases, MFC TCR-Vβ repertoire analysis demonstrated a restricted expansion of a single Vβ family in 67.5% of cases, while a "clonogram-off" pattern inferred clonality in the remaining 32.5%. For 215 (70%) patients, both MFC TCR-Vβ repertoire analysis and molecular analysis of TCR gene rearrangements were available, showing an absolute concordance (215 out of 215 cases, 100%) between the two methods.

Conclusion

MFC TCR-Vβ repertoire analysis is a rapid, cheap, sensitive, and reliable tool to identify clonal T-cell lymphocytosis. It represents an absolutely valid first-line diagnostic approach, and it should be included in the routine laboratory work-up performed on MFC analysis for peripheral lymphocytosis.

Sinonasal adenosquamous carcinomas arising in seromucinous hamartoma or respiratory epithelial adenomatoid hamartoma with atypical features: Report of five detailed clinicopathological and molecular characterisation of rare entity

AIMS

Sinonasal adenosquamous carcinoma (ASC) is a rare tumour classified as a variant of squamous cell carcinoma, exhibiting both squamous and glandular differentiation. ASC has a poorer prognosis compared to sinonasal mucoepidermoid carcinoma (MEC), another uncommon tumour in this region. ASC is believed to originate from metaplastic squamous epithelium, though it may also arise from respiratory epithelium in respiratory epithelial adenomatoid hamartoma (REAH) or seromucinous glands in seromucinous hamartoma (SH).

METHODS AND RESULTS

Five cases of sinonasal ASC were retrieved from our registry. Initially, they were classified as sinonasal MEC (n = 3), ASC (n = 2), and carcinoma ex REAH (n = 1). All cases showed adenosquamous malignant proliferation beneath the surface respiratory epithelium with occasional squamous metaplasia, except for one case that showed dysplasia. The respiratory epithelium exhibited an inverted growth pattern consistent with REAH/SH, and displayed atypical sinonasal glands (ASGSH) arising within seromucinous hamartoma. Next-generation sequencing (NGS) revealed multiple pathogenic mutations in two cases, and in case 4 GGA2::PRKCB and EYA2::SERINC3 gene fusions. One case was positive for high-risk HPV. None of the cases exhibited CRTC1/3::MAML2 gene fusion.

CONCLUSION

The connection between ASGSH and ASC has not been described in the literature. There is a growing need for additional studies on the morphological, immunohistochemical, and genetic aspects of these tumours. SH/REAH may serve as precursor lesions in the progression of atypical sinonasal glands to malignancy, and their role in tumour development deserves further investigation.

Molecular Profiling of Sinonasal Adenoid Cystic Carcinoma: Canonical and Noncanonical Gene Fusions and Mutation

Adenoid cystic carcinomas (AdCC) of salivary gland origin have long been categorized as fusion-defined carcinomas owing to the almost universal presence of the gene fusion MYB::NFIB , or less commonly MYBL1::NFIB. Sinonasal AdCC is an aggressive salivary gland malignancy with no effective systemic therapy. Therefore, it is urgent to search for potentially targetable genetic alterations associated with AdCC. We have searched the authors' registries and selected all AdCCs arising in the sinonasal tract. The tumors were examined histologically, immunohistochemically, by next generation sequencing (NGS) and/or fluorescence in situ hybridization (FISH) looking for MYB/MYBL1 and/or NFIB gene fusions or any novel gene fusions and/or mutations. In addition, all tumors were tested for HPV by genotyping using (q)PCR. Our cohort comprised 88 cases of sinonasal AdCC, predominantly characterized by canonical MYB::NFIB (49 cases) and MYBL1::NFIB (9 cases) fusions. In addition, noncanonical fusions EWSR1::MYB ; ACTB::MYB; ESRRG::DNM3 , and ACTN4::MYB were identified by NGS, each of them in 1 case. Among nine fusion-negative AdCCs, FISH detected rearrangements in MYB (7 cases) , NFIB (1 case), and EWSR1 (1 case). Six AdCCs lacked fusions or gene rearrangements, while 11 cases were unanalyzable. Mutational analysis was performed by NGS in 31/88 (35%) AdCCs. Mutations in genes with established roles in oncogenesis were identified in 21/31 tumors (68%), including BCOR (4/21; 19%), NOTCH1 (3/21; 14%), EP300 (3/21; 14%), SMARCA4 (2/21; 9%), RUNX1 (2/21; 9%), KDM6A (2/21; 9%), SPEN (2/21; 9%), and RIT1, MGA, RB1, PHF6, PTEN, CREBBP, DDX41, CHD2, ROS1, TAF1, CCD1, NF1, PALB2, AVCR1B, ARID1A, PPM1D, LZTR1, GEN1 , PDGFRA , each in 1 case (1/21; 5%). Additional 24 cases exhibited a spectrum of gene mutations of uncertain pathogenetic significance. No morphologic differences were observed between AdCCs with MYBL1::NFIB and MYB::NFIB fusions. Interestingly, mutations in the NOTCH genes were seen in connection with both canonical and noncanonical fusions, and often associated with high-grade histology or metatypical phenotype, as well as with poorer clinical outcome. Noncanonical fusions were predominantly observed in metatypical AdCCs. These findings emphasize the value of comprehensive molecular profiling in correlating morphologic characteristics, genetic landscape, and clinical behavior in AdCC.

Sinonasal adenoid cystic carcinomas accompanied by seromucinous hamartoma and/or atypical sinonasal glands arising from seromucinous hamartoma: insight into their histogenesis

The pathology of reactive, dysplastic, and neoplastic sinonasal seromucinous glands is complex, and their contribution to tumorigenesis of sinonasal carcinomas remains controversial. In our practice, we have observed the presence of respiratory epithelial adenomatoid hamartomas (REAH) and seromucinous hamartomas (SH) associated with adenoid cystic carcinomas (AdCC) in a subset of cases. In many of these cases, genuine atypical features and dysplastic characteristics of the glands were noted at the interface of SH and AdCC. To investigate this phenomenon further, 88 sinonasal AdCC cases were selected from the authors' files and analyzed histologically, immunohistochemically, and genetically searching for MYB/MYBL1 and NFIB gene fusions. HPV testing was also performed. Univariate statistical analysis was conducted on our cohort. Thirty-one cases (35%) showed features of atypical sinonasal glands arising in SH (ASGSH) at the SH-AdCC interface, characterized by bilayered epithelium, architectural disarray, mild nuclear polymorphism, and atypia, sometimes with colloid-like material in the lumen. The MYB immunomarker was negative in 14 ASGSHs (with a positive internal control in AdCC cells), while only two cases showed faint and moderate to weak expression of the antibody in ASGSH glands. In 12 cases, the immunostaining of ASGSH could not be properly assessed, while AdCC cells were negative. The immunostaining was not performed in five cases. Our findings suggest that a subset of sinonasal AdCC may originate in a multistep dysplastic process within SH, consistent with an SH-ASGSH-AdCC progression sequence.

Disease diagnostics using machine learning of B cell and T cell receptor sequences

Clinical diagnosis typically incorporates physical examination, patient history, various laboratory tests, and imaging studies but makes limited use of the human immune system's own record of antigen exposures encoded by receptors on B cells and T cells. We analyzed immune receptor datasets from 593 individuals to develop MAchine Learning for Immunological Diagnosis, an interpretive framework to screen for multiple illnesses simultaneously or precisely test for one condition. This approach detects specific infections, autoimmune disorders, vaccine responses, and disease severity differences. Human-interpretable features of the model recapitulate known immune responses to severe acute respiratory syndrome coronavirus 2, influenza, and human immunodeficiency virus, highlight antigen-specific receptors, and reveal distinct characteristics of systemic lupus erythematosus and type-1 diabetes autoreactivity. This analysis framework has broad potential for scientific and clinical interpretation of immune responses.

Adiponectin reduces immune checkpoint inhibitor-induced inflammation without blocking anti-tumor immunity

Immune-related adverse events (irAEs) in cancer patients receiving immune checkpoint inhibitors (ICIs) cause morbidity and necessitate cessation of treatment. Comparing irAE treatments, we find that anti-tumor immunity is preserved in mice after extracorporeal photopheresis (ECP) but reduced with glucocorticosteroids, TNFα blockade, and α4β7-integrin inhibition. Local adiponectin production elicits a tissue-specific effect by reducing pro-inflammatory T cell frequencies in the colon while sparing tumor-specific T cell development. A prospective phase-1b/2 trial (EudraCT-No.2021-002073-26) with 14 patients reveals low ECP-related toxicity. Overall response rate for all irAEs is 92% (95% confidence interval [CI]: 63.97%-99.81%); colitis-specific complete remission rate is 100% (95% CI: 63.06%-100%). Glucocorticosteroid dosages could be reduced for all patients after ECP therapy. The ECP-adiponectin axis reduces intestinal tissue-resident memory T cell activation and CD4+IFN-γ+ T cells in patients with ICI-induced colitis without evidence of loss of anti-tumor immunity. In conclusion, we identify adiponectin as an immunomodulatory molecule that controls ICI-induced irAEs without blocking anti-tumor immunity.

Identification of clonally expanded T-cell receptor sequences in giant cell arteritis

BACKGROUND

Arterial wall inflammation in giant cell arteritis (GCA) is characterized by T-cell infiltration and granuloma formation. There have been limited studies investigating the diversity of the T-cell receptor (TCR) repertoire in GCA patients. Here we aim to identify disease-relevant TCRs.

METHODS

We sequenced the TCRβ repertoires in peripheral blood and biopsies from 72 GCA patients and compared them to repertoires of 60 age-matched controls. Applying K-nearest neighbours classification based on tcrdist3, an established TCR similarity measure, we identified GCA-associated TCRs across multiple model hyperparameters and experimental replicates.

RESULTS

We observed that species richness and Shannon diversity were significantly lower (P = 0.0003 and P = 0.004, respectively) in GCA peripheral blood TCR repertoires compared with age-matched controls. 1526 TCRs were identified that were consistently associated with GCA, 63 TCRs were also detected in TAB repertoires. Identical GCA-associated TCRs were observed in paired blood and tissue samples from 21/30 GCA cases. 57 % of GCA-associated TCRs were fitted into 10 clusters, which displayed distinct TCR sequences and TCR V and J segment usage. TRBV20-1∗01, TRBV4-3∗01, TRBV4-2∗01 and TRBV4-1∗01 segments were over-represented and occurred at least 10 % more often among GCA patients than age-matched controls. Only 27/1526 TCR sequences had matches reported in public databases, reducing the likelihood that these targeted common infectious agents.

CONCLUSIONS

Our data provide evidence of circulating T-cell clonal expansions in GCA patients. Certain TCR sequence patterns were over-represented in GCA subjects. As more TCR sequences directed at human antigens become available, further analysis may ultimately reveal whether these TCRs bind a common target antigen.

Evaluation of T-cell repertoire by flow cytometric analysis in primary immunodeficiencies with DNA repair defects

The group of patients with DNA-repair-defects increases susceptibility to infections due to impaired repertoire diversity. In this context, we aimed to investigate the TCRvβ-repertoire by flow cytometric analysis and its correlation with clinical entities in a group of IEI patients with DNA repair defects. Peripheral lymphocyte subset and TCRvβ-repertoire analyses were performed by flow cytometric analysis. The aim was to explore the changing TCR-Vβ-repertoire that can predict some clinical entities by investigating the repertoire using flow-cytometric-analysis-based TCR-Vβ and its interaction with clinical entities in a group of IEI patients with DNA repair defects. TCR-repertoire of the patients with DNA-repair-defects and healthy controls was analysed with flow-cytometer. The potential of flow-cytometric analysis of the TCR repertoire as a practical and easily accessible clinical prediction method was investigated. Thirty-nine-IEI patients with DNA-repair-defects and 15 age-matched healthy-controls were included in this study. Peripheral lymphocyte subset and TCR-Vβ repertoire analyses were performed by flow cytometry. Compared to the control group, 9 out of 24 clones (37.5%) exhibited a statistically significant reduction, while only 3 clones showed a statistically significant increase (p < 0.05). Preferential use of vβ-genes was associated with some clinical entities. Lower TCR-vβ-9 and TCR-vβ23, higher TCR-vβ7.2 were found in the patients with pneumonia (n = 13) (p = 0.018, p = 0.044 p = 0.032). AT patients with pneumonia had lower TCR-vβ-9 clone than patients without pneumonia (p = 0.008). Skewed proliferation of most TCR-vβ clones was seen DNA-repair-defects, especially AT. In addition, this study showed that preferential use of TCR-vβ genes could be predictive for some clinical entities.

Anti-retinal immune response in sarcoid uveitis: A potential role for PCLO as an antigenic target

PURPOSE

To explore the autoimmune component of sarcoid uveitis (SU) by analyzing serum anti-retinal antibodies (ARAs), identifying targeted retinal proteins, T- and B-cell receptor repertoires and HLA genotype.

METHODS

Material from 45 sarcoidosis patients with no presenting uveitis (SNPU) and 46 with SU was analyzed. Serum ARAs and targeted retinal layers were assessed using indirect immunofluorescence staining. HuScan analysis identified autoantibody-targeted linear epitopes. Validation included a bead-based assay for anti-Piccolo Presynaptic Cytomatrix Protein (PCLO) antibodies and an ELISpot assay for PCLO-reactive T-lymphocytes. T cell receptor beta (TCRB) and B cell receptor heavy (BCRH) repertoire analyses were performed using next-generation sequencing and HLA class II genotypes were determined by sequence-specific primer analysis.

RESULTS

ARAs were more prevalent in SU patients than in SNPU patients (52 vs. 22 %, p = 0.003), with significant more reactivity against the nuclear retinal layer (32 vs. 7 %, p = 0.005). HuScan identified autoantibodies against three retinal proteins, including PCLO. Bead-based analysis showed higher anti-PCLO autoantibody levels in ARA-positive patients (median: 913.3 vs. 544.5, p = 0.035), and PCLO-directed T-lymphocytes were present in ARA-positive SU patients. Two TCRB clusters were identified in four unique ARA positive patients, while absent in ARA negative patients. No HLA allele association with ARA status could be detected.

CONCLUSION

Our findings reveal an association between serum ARA-positivity and SU, suggesting a link to autoimmune processes. An humoral and cellular response against the retinal protein PCLO was identified, highlighting PCLO as a potential autoimmune target in ARA-positive patients. Additionally, specific TCRB clusters were found to correlate with ARA status.

Differential Expression of p53 in Mycosis Fungoides, Sezary Syndromes, and Their Transformed Forms

ABSTRACT

Mycosis fungoides (MF) and Sezary syndrome (SS) are common entities among primary cutaneous lymphomas. Large cell transformation is challenging for diagnosis and therapy. Molecular mechanisms by which these lymphomas undergo this transformation are poorly defined. We studied the immunohistochemical status of p53 in these entities and assessed whether p53 expression could be a useful tool for diagnosis and assessment of transformation. We extracted patients with transformed and untransformed SS or MF from the French Study Group on Cutaneous Lymphoma database between 2014 and 2021, followed in the Rennes University Hospital. An immunohistochemical study of p53 expression was performed on the biopsies sampled as part of routine care. We compared p53 overexpression in the different groups. We included 25 patients with MF, 7 patients with transformed MF (T-MF), 11 patients with SS, and 5 patients with transformed SS (T-SS). Using a cut-off set at 30% expression of neoplastic cells, we noted an overexpression of p53 in T-MF and T-SS compared with nontransformed forms (47% vs. 12%, respectively, P < 0.01) and in MF compared with SS (23% vs. 7%, respectively, P < 0.01). Overexpression of p53 with a cut-off at 30% therefore seems to be a discriminating tool in the differential diagnosis of MF/SS versus their transformed forms as well as the differential diagnosis between MF and SS.

[T-cell large granular lymphocytic leukemia and Felty's syndrome in rheumatoid arthritis]

Neutropenia in rheumatoid arthritis (RA) is a problem that often needs to be addressed. Side effects of basic antirheumatic treatment, infections or substrate deficiencies are common causes; however, T‑cell large granular lymphocytic (T-LGL) leukemia, a mature T‑cell neoplasm, can also lead to autoimmune cytopenia. The T‑LGL leukemia can be associated not only with RA but also with other autoimmune diseases or neoplasms. Correspondingly, increases in clonal T cells, natural killer T (NKT) cells and LGL cells are found in the peripheral blood. A T‑cell receptor PCR and flow cytometry (or at least a blood smear) are therefore necessary to diagnose T‑LGL leukemia. The presence of clonal T cells alone is usually not pathological. A distinction must be made from Felty's syndrome (consisting of the clinical triad of arthritis, leukopenia, splenomegaly), which does not require the two T‑LGL leukemia criteria mentioned. The treatment for both entities (with underlying RA) is methotrexate and, if insufficiently effective, rituximab.

Robust HPV-16 Detection Workflow for Formalin-Fixed Cancer Tissue and Its Application for Oral Squamous Cell Carcinoma

BACKGROUND

Virus-related cancers are malignancies caused by specific viruses, such as human papillomavirus (HPV), hepatitis B virus, and human T-cell leukemia virus, contributing significantly to the global cancer burden through persistent infection and oncogenic transformation. The current study aimed to develop a robust HPV-16 detection method for formalin-fixed cancer specimens.

MATERIALS AND METHODS

To prevent false negatives resulting from DNA fragmentation, a DNA quality check step was added. Additionally, this study used multiplex polymerase chain reaction (PCR) covering the entire HPV-16 genome to mitigate effects caused by viral sequence variation. To prove this concept, we analyzed genomic DNA extracted from oropharyngeal cancer tissues known as HPV-16-positive. Subsequently, the protocol was tested on oral squamous cell carcinoma (OSCC) samples in our cohort. Given the wide variation in HPV-16 positivity in previous studies, it remains elusive how frequently HPV-16 is positive in OSCC.

RESULTS

The results showed faint bands or smears in the multiplex PCR of 7 out of 112 cases. Droplet digital PCR confirmed variable positivity levels of HPV-16, suggesting two scenarios of HPV-16 positivity in cancer tissue: cancer cells derived from infected cells or only a portion being HPV-16-positive. Finally, we comprehensively analyzed the case and identified the integration of a deleted HPV-16 genome into the intronic region of the host gene TMEM94 on chromosome 17. To the best of our knowledge, this is the first evidence showing the integration of HPV-16 in OSCC cells and providing its complete viral sequence.

CONCLUSIONS

The established protocol should be applicable to various cancer tissues for analyzing the association with HPV-16 infection.

The Diagnostic Utility of TRBC1 Immunohistochemistry in Mature T-Cell Lymphomas

T-cell clonality assessment constitutes an essential part of the diagnostic evaluation of suspected T-cell neoplasms. Recent advances in flow cytometry-based analysis of TCR β-chain constant region 1 (TRBC1) have introduced an accurate method of assessment of T-cell clonality. Its broader applicability is constrained due to the requirement of viable cells. Furthermore, the utility of the TRBC1 antibody in tissue immunohistochemistry (IHC) has not been comprehensively addressed. Herein, we validated an IHC-based approach to assess T-cell clonality using formalin-fixed, paraffin-embedded tissue. Utilizing DeepLIIF image analysis, we quantified TRBC1 positivity among CD3-positive cells in a training cohort comprising 34 cases of α/β T-cell neoplasms and 29 cases of reactive lymphoid tissue as controls. In an independent validation cohort comprising 29 T-cell neoplasms and 20 controls, similar image quantification was conducted by a pathologist uninvolved in the analysis of the training cohort and blinded to the diagnoses. Receiver operating characteristic analysis of the training cohort established the optimal cutoff points for monotypic TRBC1 expression-79.0% or higher indicating monotypic positivity and 36.3% or lower denoting negativity. These thresholds demonstrated robust metrics in both the training (sensitivity 88.2%, specificity 93.1%, positive predictive value 93.8%, negative predictive value 87.1%) and the validation cohorts (sensitivity 93.1%, specificity 95.0%, positive predictive value 96.4%, negative predictive value 90.5%). TRBC1 IHC was correlated with flow cytometry in 52 cases, which demonstrated a strong quantitative correlation of TRBC1 positivity (r = 0.78; P <.001) and a high categoric agreement (85.9%) in classifying monotypic versus polytypic staining. Discrepancies in categorization were associated with low tumor percentages. Furthermore, multiplex immunofluorescence was performed in 15 cases for targeted quantification of TRBC1 expression in CD3-positive, PAX5-negative cells, achieving a concordance of 86.7% with IHC. In summary, TRBC1 IHC offers a reliable and practical complementary method for assessing T-cell clonality.

An exploratory study on the differential diagnostic indicators between adult systemic EBV-positive T-cell lymphoproliferative disorders and angioimmunoblastic T-cell lymphoma with multiple EBV infections

BACKGROUND

The differential diagnosis between adult systemic EBV-positive T-cell lymphoproliferative disorders (EBV+ T-LPD) and angioimmunoblastic T-cell lymphoma (AITL) with multiple EBV infections is difficult, and distinguishing between the two has become a diagnostic challenge for pathologists. Given that the clinical treatment plans are different, an accurate diagnosis is a prerequisite to ensure effective treatment, therefore, it is extremely necessary and meaningful to find effective pathological indicators for distinguishing between two diseases.

METHODS

We present a retrospective study comparing 7 cases of adult EBV+ T-LPD and 16 cases of AITL with multiple EBV infections diagnosed at our institution from 2017 to 2022. Differences in immunophenotype, type of EBV-infected cells, clonality and gene mutations between the two groups of cases were compared by immunohistochemical staining, double-label staining, TCR gene rearrangement and next-generation sequencing analysis.

RESULTS

7 cases of adult EBV+ T-LPD: all cases had no more than 1 T follicular helper (THF) marker was expressed, and there were significantly more EBER+/CD3 + cells than EBER+/CD20 + cells; 5 cases had mutation detection results, in which only 1 had the characteristic KMT2D mutation, 2 had TET2 mutations, and no common mutations such as DDX3X were detected.16 cases of AITL with multiple EBV infections: all cases were found to express at least 2 TFH markers, with 87% of them expressing at least 3 TFH markers., and had significantly more EBER+/CD20 + cells than EBER+/CD3 + cells; 4 cases had mutation test results, with mutated high-frequency genes being TET2 (100%, and all of them had 2 or more TET2 mutations) and RHOA G17V (100%), DNMT3A mutation occurred in 2 cases (50%), and IDH2 R172 mutation occurred in 1 case (25%).

CONCLUSIONS

We found that the expression pattern of TFH markers, the types of cells predominantly infected by EBV and the different mutations can all be used as effective pathological indicators for distinguishing between two diseases.

PCR GeneScan Analysis of Rearranged Immunoglobulin or T-Cell Receptor Genes for Clonality Diagnostics in Suspect Lymphoproliferations

Assessment of the presence of clonal lymphoproliferations via polymerase chain reaction (PCR)-based analysis of rearranged immunoglobulin (IG) or T-cell receptor (TR) genes is a valuable method in the diagnosis of suspect lymphoproliferative disorders. Additionally, this methodology can be used for evaluating dissemination of lymphoma cells and for studying the clonal relationship between multiple (different locations) and consecutive (over time) lymphomas. Here we describe an integrated approach to assess clonality via analysis of Ig heavy chain (IGH), Ig kappa (IGK), TCR beta (TRB), and TCR gamma (TRG) gene rearrangements, based on the standardized multiplex PCRs as originally developed by the European BIOMED-2 consortium (currently named EuroClonality). The described protocol covers the pre-analytical phase of DNA isolation (from formalin-fixed paraffin-embedded and fresh tissues, body fluids, peripheral blood, and bone marrow), the analytical phase of PCR GeneScan analysis, and the post-analytical interpretation of the obtained profiles, following established guidelines.

Paediatric cutaneous lymphomas including rare subtypes: A 40-year experience at a tertiary referral centre

BACKGROUND

Primary cutaneous lymphomas are neoplasms of the immune system with a distinct tropism for the skin and an absence of extracutaneous manifestations at the time of diagnosis. Studies focusing on cutaneous lymphomas in children and adolescents remain scarce and often do not encompass the rare subtypes.

OBJECTIVES

To address this knowledge gap by describing the clinical, histological and molecular characteristics of a large group of paediatric patients affected by primary cutaneous lymphoma. We also provided the Paediatric Primary Cutaneous Lymphoma Atlas that illustrates the clinicopathological spectrum of observed presentations, in the hope of supporting other physicians in the diagnostic process.

METHODS

Retrospective chart review of paediatric patients diagnosed with primary cutaneous lymphomas between 1980 and 2022 at the Paediatric Dermatology Unit of Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan.

RESULTS

A total of 101 patients (58 males, 43 females) met the inclusion criteria. The most common subtypes were lymphomatoid papulosis (n = 48) and mycosis fungoides (n = 31). These were followed by primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorders (n = 7), primary cutaneous anaplastic large-cell lymphomas (n = 5), primary cutaneous marginal zone B-cell lymphomas (n = 3), primary cutaneous follicle centre lymphomas (n = 2), subcutaneous panniculitis-like T-cell lymphomas (n = 2), primary cutaneous peripheral T-cell lymphoma not otherwise specified (n = 1), primary cutaneous precursor B-lymphoblastic lymphoma (n = 1) and Sézary syndrome (n = 1). Clinical follow-up data covering a median of 70.8 months (range 1-324) were available for 74 patients, of whom three died due to cutaneous lymphoma.

CONCLUSIONS

Our findings shed light on the peculiar aspects and long-term outcomes of paediatric cutaneous lymphomas, particularly emphasizing their distinctive features in comparison to their adult counterparts and exploring the less common subtypes. Further larger-scale studies are warranted to better characterize these entities and to achieve a more rapid and accurate diagnosis.

MRD Detection in B-Cell Non-Hodgkin Lymphomas Using Ig Gene Rearrangements and Chromosomal Translocations as Targets for Real-Time Quantitative PCR and ddPCR

Minimal residual disease (MRD) diagnostics is of high clinical relevance in patients with indolent B-cell non-Hodgkin lymphomas (B-NHL), B-cell chronic lymphocytic leukemia (CLL), and multiple myeloma and serves as a surrogate parameter to evaluate treatment effectiveness and long-term prognosis. Real-time quantitative PCR (RQ-PCR) targeting circulating lymphoma cells is still the gold standard for MRD detection in indolent B-NHL and currently the most sensitive and the most broadly applied method in follicular lymphoma (FL) and mantle cell lymphoma (MCL). Alternatively, droplet digital PCR (ddPCR) can be used for MRD monitoring in multiple myeloma, mantle cell lymphoma, CLL, and FL with comparable sensitivity, accuracy, and reproducibility.The most broadly applicable MRD target in B-NHL is the junctional regions of the rearranged immunoglobulin heavy (IGH) and light chain genes. Complete and incomplete IGH and additionally IG kappa light chain rearrangements can be used as targets for MRD. Next-generation sequencing (NGS) of IG-rearrangements (IG-NGS) as new sequencing-based technology can overcome the limitation of PCR-based approaches and has a potential for higher sensitivity. Chromosomal translocations like the t(14;18)(q32;q21) translocation associated with IGH::BCL2 fusion in FL and t(11;14)(q13;q32) translocation in MCL leading to the IGH::CCND1 fusion can be used as MRD target in selected lymphoma subtypes. In patients with CLL, both flow-cytometry and RQ-PCR are equally suited for MRD assessment as long as a sensitivity of 10-4 is achieved.MRD diagnostics targeting the IG loci is complex and requires extensive knowledge and experience because the junctional regions of each clonal rearranged gene have to be identified before the patient-specific PCR assays can be designed for MRD monitoring. In addition, the presence and load of somatic hypermutation within the rearranged IGH gene occurring during B-cell development of germinal center and post-germinal center B-cell lymphomas may hamper appropriate primer binding leading to false-negative results. The translocations mentioned above have the advantage that consensus forward primers and probes, both placed in the breakpoint regions of chromosome 18 in FL and chromosome 11 in MCL, can be used in combination with a reverse primer placed in the IGH joining region of chromosome 14. PCR-based methods using allele-specific primers can reach a high sensitivity of up to 10-5. This chapter provides all relevant background information and technical aspects for the complete laboratory process from detection of the clonal IG gene rearrangements and the chromosomal translocations at diagnosis to the actual MRD measurements in clinical follow-up samples of B-NHL. However, it should be noted that MRD diagnostics for clinical treatment protocols has to be accompanied by regular international quality control rounds to ensure the reproducibility and reliability of the MRD results. This is available by the EuroMRD network ( https://euromrd.org ), a subgroup of ESHLO ( https://eslho.org ).

Formalin-free tissue embedding is less hazardous and results in better DNA quality

Disease diagnosis, prognosis, and therapy choice progressively rely on good-quality Deoxyribonucleic acid (DNA) for molecular analysis. As tissue processing is routinely performed worldwide with ancient techniques using toxic and DNA-damaging formaldehyde, the quality of DNA isolated from embedded tissues used for diagnostics is poor. We used a novel formalin-free tissue embedding method to process tissues and show that, after 5 years, DNA quality is superior to formalin fixation.

EXPRESSION OF IMMUNOGLOBULIN LIGHT CHAIN GENES IN STEREOTYPED CASES FROM UKRAINIAN COHORT OF CHRONIC LYMPHOCYTIC LEUKEMIA PATIENTS

BACKGROUND

Analysis of immunoglobulin heavy chain gene (IGHV) rearrangements expressed in chronic lymphocytic leukemia (CLL) cells has provided insights into the B-cell receptor (BCR) repertoire in CLL. In more than 40% of CLL patients, (quasi)identical or stereotyped BCR is expressed. The recent data point at the non-stochastic expression of immunoglobulin light lambda (IGLV) or kappa (IGKV) chains as well. Several pairs of IGHV and IGK/LV have been described for some major stereotyped subsets, but most subsets have not been characterized.

AIM

To study the IGK/LV gene expression in stereotyped CLL cases.

MATERIALS AND METHODS

Analysis was performed in a group of 105 CLL patients with stereotyped BCR. The cases with stereotyped BCRs were identified according to Agathangelidis et al. (2021). The IGHV and IGK/LV gene expressions were studied by a polymerase chain reaction followed by direct sequencing.

RESULTS

The expression of the IGK/LV genes in the most presented major stereotyped subsets (#1, #2, #3C3, #4, #6, #28а) was in agreement with the data reported by other authors. For the cases of subsets #5b, #9D1, #9D4, #16, #50, #59, and #77, differences were found. The new data on the IGK/LV gene expression in 55 minor clusters were presented. A number of patterns of the IGK/LV gene expression depending on the phylogenetic clan and mutational status of the IGHV genes have been described.

CONCLUSION

The non-stochastic distribution of the IGKV/LV gene expression in the individual stereotyped subsets was confirmed. Taking into account the complementary role of the light chains in antigen recognition by the clonotypic BCRs, it was suggested that the subsets with the heterogeneous IGK/LV expression might be reclassified and divided into separate subgroups based on the IGHV and IGK/LV association.

Clonal T cell populations scarcely impair patients with rheumatic diseases: a prospective long-term follow up study

BACKGROUND

Clonal T cell populations are frequently detected in patients with rheumatic diseases. The relevance of this finding is often uncertain, as the clinical spectrum can range from being asymptomatic to T cell leukemia. Former studies suggested that certain anti-rheumatic drugs might influence the course of the clonal T cell populations.

METHODS

A prospective long-term follow up study was performed including patients with rheumatic diseases and clonal T cell populations. Clinical features, adverse events, especially infections and cytopenias, and immunosuppressive medication were assessed. T cell populations were characterized by polymerase chain reaction, flow cytometry and stimulated cell cultures.

RESULTS

28 Patients with rheumatoid arthritis, spondyloarthritis, or giant cell arteritis were prospectively followed for up to 7.6 years. Severe infections or cytopenias (10.7% autoimmune neutropenias) were rare. The clonal T cell populations mostly persisted over time, the tumor burden decreased in the long-term. The cytokine secretion in stimulated T cell cultures did not differ in the subgroup of RA patients with versus without clonal T cells.

CONCLUSION

Clonal T cell populations in patients with rheumatic diseases are common, but are rarely harmful. Feared neutropenia, infections or progression into T cell leukemia could not be detected in the long-term in our cohort.

Paraneoplastic glomerulonephritis and kidney infiltration by mantle cell lymphoma: A diagnostic challenge

Mantle cell lymphoma (MCL) is a rare and aggressive type of lymphoma that can affect the kidneys. The disease can lead to kidney impairment, and glomerulonephritis (GN) is a rare but serious complication of MCL. We report a case of MCL with kidney interstitial infiltration and membranoproliferative glomerulonephritis with focal and segmental glomerulosclerosis. A 75-year-old man presented recurrent acute kidney failure and worsening of nephrotic syndrome. Kidney biopsy revealed membranoproliferative glomerulonephritis presented immunoglobulin and complement deposition, focal and segmental glomerulosclerosis of not otherwise specified type, and infiltration by mantle cell lymphoma. Bone marrow biopsy and PET/CT scan confirmed the diagnosis of mantle cell lymphoma. The patient was treated with R-CHOP21 chemotherapy with cyclophosphamide dose adjustment for nephroprotection. He achieved complete remission with normalization of hematological parameters, improvement of kidney function, and reduction of proteinuria and albuminuria. This case shows the importance of considering alternative diagnoses in patients with recurrent chronic kidney disease and worsening nephrotic syndrome. Early diagnosis and treatment of mantle cell lymphoma can lead to favorable outcomes.

CREBBP is a Major Prognostic Biomarker for Relapse in Childhood B-cell Acute Lymphoblastic Leukemia: A National Study of Unselected Cohort

Although the identification of disease subtypes conveying prognostic significance along with minimal residual disease (MRD) assessment represent cornerstones for stratification in childhood acute lymphoblastic leukemia (ALL), approximately half of the relapses occur in patients from standard-risk groups. Identification of the drivers of treatment failure is crucial for detection of high-risk clones at diagnosis. We evaluated clinical variables and the most common genetic alterations in an unselected cohort of 55 patients with B-ALL treated according to the ALL-IC-BFM 2002 protocol, with a median follow-up of 46 months. Matched diagnosis-relapse samples underwent screening for additional alterations using whole-exome sequencing. Mutations in the CREBBP gene were found in 80% (4/5) of the patients with relapse, either present from the disease onset or acquired at relapse, while none of the examined patients in remission presented alterations in this gene. Deletions in TP53 and EBF1 (present in 2/5 and 1/5 of the patients with relapse, respectively) were infrequent or absent in the patients in remission, respectively. Screening for alterations in the CREBBP gene at diagnosis and/or at multiple time-points during chemotherapy could be incorporated into treatment protocols, as it may contribute to the identification of significant number of patients with predefined or acquired chemoresistant clones.

Intraparenchymal low-grade B-cell lymphomas of the central nervous system: Clinicopathologic and molecular analysis of three cases and a review of the literature

Primary central nervous system (CNS) lymphomas represent 1 % of all non-Hodgkin lymphomas, with diffuse large B-cell lymphomas as the prevailing subtype. Low-grade B-cell lymphomas are exceptional with only 24 marginal zone B-cell lymphomas (EMZL) and 1 follicular lymphoma (FL) previously reported so far. While their molecular profiles are studied elsewhere, data on primary intraparenchymal CNS cases remain limited. The objective of the present study is to contribute new cases of primary intraprenchymal low-grade B-cell lymphomas in the CNS and characterize their mutational profile. We conducted a comprehensive review of cases and a literature review to identify similar instances. Clinical, imaging, histological, immunohistochemical, and molecular characteristics were analyzed. Diagnoses were established according to established criteria. We present three novel cases of intraparenchymal CNS low-grade B-cell lymphomas. One case of intraparenchymal EMZL exhibited plasmacytic differentiation, while another lacked a plasma cell component. The third case was diagnosed as FL. The L265P mutation of MYD88 was absent in all cases. Next generation sequencing revealed pathogenic mutations in SPEN (Glu1970ValfsTer64) and ARID1A (Pro1355LeufsTer118) genes in one EMZL case. In conclusion, intraparenchymal CNS low-grade B-cell lymphomas are rare, with few reported cases. Our findings expand knowledge on their clinical and molecular features. We present the first molecular profile of primary CNS intraparenchymal EMZL, underscoring the need for further research to understand their biology and optimize treatment strategies.

Adult-Onset Pediatric-Type Follicular Lymphoma of the Parotid Gland

Pediatric-type follicular lymphoma (PTFL) is an extremely rare B-cell lymphoma that primarily affects children and young adults, typically in individuals under 25 years old, with a median age of 15 years. Here, we report a rare case of PTFL in a 27-year-old adult male who presented with a slow-growing mass near his left ear. Initial CT scans of the neck revealed two oval-shaped, smooth, well-defined, homogeneously enhancing soft tissue density lesions in the superficial lobe of the left parotid gland. A complete surgical excision was performed, and a postoperative ultrasound of the neck confirmed complete removal, with only hypoechoic changes observed in the parotid gland. Comprehensive immunohistochemical analysis showed CD20-positive B cells co-expressing germinal center markers CD10 and BCL6 but negative for BCL2 and cyclin D1. The Ki-67 proliferation index was notably elevated, indicating high cellular activity. Additional findings included MEF2B positivity, confirming the lymphoma diagnosis, and an immunoglobulin gene rearrangement, which demonstrated a monoclonal B-cell population consistent with a neoplastic process. CD21 staining further revealed distorted follicular dendritic cell networks and attenuated IgD-positive mantle. Fluorescence in situ hybridization (FISH) analysis showed no rearrangements in BCL2, IRF4, or BCL6, and any deletion in the 1p36 region (TNFRSF14 gene), ruling out other lymphoma types. Histologically, the nodules showed distorted secondary follicles with obscured germinal centers, confirming PTFL. At the three-month follow-up, the patient demonstrated satisfactory healing with no signs of recurrence. This case underscores the importance for oncologists to perform a thorough differential diagnosis of head and neck masses, as PTFL can present with characteristics similar to classical follicular lymphoma, IRF4-rearranged large B-cell lymphoma, pediatric nodal marginal zone lymphoma, and reactive follicular hyperplasia. A comprehensive diagnostic approach, including clinical, pathological, and immunohistochemical analyses, is essential for developing an accurate diagnosis and management plan for PTFL, especially in atypical adult presentations.

Demonstration of T-Cell Monotypia Using Anti-TCRbeta1/2 (TRBC1/2) Immunostaining as a Rapid and Cost-Effective Alternative to PCR-Based Clonality Studies for the Diagnosis of T-Cell Lymphoma

BACKGROUND/OBJECTIVES

T-cell lymphomas are often histologically indistinguishable from benign T-cell infiltrates, and diagnosis typically relies on slow, complex, and expensive multiplexed PCR reactions, requiring significant training and experience to interpret them. We aimed to raise highly specific antibodies against the two alternatively used and very similar T-cell receptor beta constant regions, TCRbeta1 and TCRbeta2, encoded by the TRBC1 and TRBC2 gene segments, respectively. We sought to demonstrate the feasibility of detecting TCRbeta1 and TCRbeta2 immunohistochemically in routine clinical (formalin-fixed, paraffin-embedded (FFPE)) tissue sections as a novel diagnostic strategy for T-cell lymphomas.

METHODS

Recombinant rabbit antibodies were validated using Western blotting and FFPE immunostaining of T-cell leukemia lines. The immunostaining of FFPE tissue containing benign and lymphomatous T-cell populations was undertaken, with corroboration by BaseScopeTM high-sensitivity in situ hybridization and quantitative real-time PCR (Q-PCR). An additional Q-PCR literature review and analysis of publicly available RNAseq data was used to determine the TCRbeta2/TCRbeta1 ratio cut-off to separate benign and malignant T-cell populations.

RESULTS

Our TCRbeta1/TCRbeta2 antibody pair gave highly specific FFPE tissue staining. All benign samples analyzed (immunohistochemically, by BaseScopeTM, by Q-PCR, and by RNAseq data analysis) had TCRbeta1/TCRbeta2 or TRBC1/TRBC2 ranges well within the previously published flow cytometric benign range (TCRbeta2/TCRbeta1 = 0.18:1-5.7:1), while samples of T-cell lymphoma did not. One out of thirteen (7.7%) lymphoma samples showed some detectable TCRbeta1/TCRbeta2 protein co-expression, and 4 out of 13 (30.8%) T-cell lymphomas showed a TRBC1/TRBC2 transcript co-expression using BaseScopeTM.

CONCLUSIONS

Analyzing T-cell monotypia immunohistochemically, analogous to B-cell monotypia (kappa: lambda ratio for B-cell and plasma cell neoplasms), could make the diagnosis of T-cell lymphomas cheaper, quicker, and more accurate. Larger studies are needed to validate our antibodies for clinical use.

DNA methylation as a new tool for the differential diagnosis between T-LBL and lymphocyte-rich thymoma

T-lymphoblastic lymphoma (T-LBL) and thymoma are two rare primary tumors of the thymus deriving either from T-cell precursors or from thymic epithelial cells, respectively. Some thymoma subtypes (AB, B1, and B2) display numerous reactive terminal deoxynucleotidyl transferase-positive (TdT+) T-cell precursors masking epithelial tumor cells. Therefore, the differential diagnosis between T-LBL and TdT+ T-lymphocyte-rich thymoma could be challenging, especially in the case of needle biopsy. To distinguish between T-LBL and thymoma-associated lymphoid proliferations, we analyzed the global DNA methylation using two different technologies, namely MeDIP array and EPIC array, in independent samples series [17 T-LBLs compared with one TdT+ lymphocyte-rich thymoma (B1 subtype) and three normal thymi, and seven lymphocyte-rich thymomas compared with 24 T-LBLs, respectively]. In unsupervised principal component analysis (PCA), T-LBL and thymoma samples clustered separately. We identified differentially methylated regions (DMRs) using MeDIP-array and EPIC-array datasets and nine overlapping genes between the two datasets considering the top 100 DMRs including ZIC1, TSHZ2, CDC42BPB, RBM24, C10orf53, and MACROD2. In order to explore the DNA methylation profiles in larger series, we defined a classifier based on these six differentially methylated gene promoters, developed an MS-MLPA assay, and demonstrated a significant differential methylation between thymomas (hypomethylated; n = 48) and T-LBLs (hypermethylated; n = 54) (methylation ratio median 0.03 versus 0.66, respectively; p < 0.0001), with MACROD2 methylation status the most discriminating. Using a machine learning strategy, we built a prediction model trained with the EPIC-array dataset and defined a cumulative score taking into account the weight of each feature. A score above or equal to 0.4 was predictive of T-LBL and conversely. Applied to the MS-MLPA dataset, this prediction model accurately predicted diagnoses of T-LBL and thymoma. © 2024 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Older Adults with Ph Negative Acute Lymphoblastic Leukemia: A Monocentric Experience on 57 Patients Focusing on Treatment Intensity and Age-Related Prognosis

Background: Treating with curative intent elderly patients affected by acute lymphoblastic leukemia (ALL) is an unmet clinical need. Comorbidities, lower tolerance to organ toxicities, and poor disease-related prognostic features make it difficult to cure these patients. Objectives: To analyze the outcome of ALL elderly patients aged over 55 years treated intensively or with the best supportive care (BSC) over the last 20 years.  

Nanopore Sequencing for T-Cell Receptor Rearrangement Analysis in Cutaneous T-Cell Lymphoma

Background: Analysis of T-cell receptor (TCR) clonality is a major diagnostic tool for lymphomas, particularly for cutaneous T-cell lymphomas (CTCL) like Mycosis fungoides and Sézary syndrome. However, a fast and cost-effective workflow is needed to enable widespread use of this method. Methods: We established a procedure for TCR rearrangement analysis via Oxford Nanopore Technology (ONT) sequencing. TCR receptor rearrangements (TCR-gamma and TCR-beta chains) were analyzed in samples from 45 patients with various diagnoses: Mycosis fungoides (37/45), Sézary Syndrome (2/45), folliculotropic CTCL (1/45), and non-CTCL diagnoses as polyclonal controls (5/45). Sample types included formalin-fixed paraffin-embedded (FFPE) samples (27/45), fresh frozen samples (9/45), and CD3-isolated cells (9/45). In addition, DNA of a Jurkat cell line was used as a monoclonal control. TCR amplicons were generated employing an optimized version of the protocol from the Euro Clonality consortium. Sequencing was conducted on the ONT GridION and Illumina MiSeq platforms, followed by similar bioinformatic analysis protocols. The tumor clone frequency (TCF), a crucial prognostic factor for CTCL patients, was used for method comparison. Results: The use of an optimized amplicon protocol and adapted bioinformatic tools demonstrated a strong correlation in TCF values between both sequencing methods across all sample types (range R: 0.992-0.996; range r2: 0.984-0.991). Conclusions: In summary, ONT sequencing was able to detect TCR clonality comparable to NGS, indicating its potential as a faster and more cost-effective option for routine diagnostic use.

Aleukemic variant of T-cell large granular lymphocyte leukemia in patients with rheumatoid arthritis - diagnostically challenging subtype

INTRODUCTION

The typical clinical manifestations of T-cell large granular lymphocyte (T-LGL) leukemia are an increase in the number of large granular lymphocytes (LGLs) in the blood > 2000 cells/μL, neutropenia, and splenomegaly. In rare cases of so-called 'aleukemic' T-LGL leukemia, the number of LGLs is <400-500 cells/μL. In patients with rheumatoid arthritis (RA), distinguishing T-LGL leukemia with low tumor burden in the blood and bone marrow from Felty syndrome (FS) poses diagnostic challenges.

AREAS COVERED

This review aimed to describe the basic characteristics and variants of aleukemic T-LGL leukemia, with a special focus on aleukemic T-LGL leukemia with massive splenomegaly (splenic variant of T-LGL leukemia) and differential diagnosis of such cases with hepatosplenic T-cell lymphoma. The significance of mutations in the signal transducer and activator of transcription 3 (STAT3) gene for distinguishing aleukemic RA-associated T-LGL leukemia from FS is discussed, along with the evolution of the T-LGL leukemia diagnostic criteria. PubMed database was used to search for the most relevant literature.

EXPERT OPINION

Evaluation of STAT3 mutations in the blood and bone marrow using next-generation sequencing, as well as a comprehensive spleen study, may be necessary to establish a diagnosis of aleukemic RA-associated T-LGL leukemia.

Increased abundance of Firmicutes and depletion of Bacteroidota predicts poor outcome in chronic lymphocytic leukemia

Evidence indicates that there are significant alterations in gut microbiota diversity and composition in patients with hematological malignancies. The present study investigated the oral and intestinal microbiome in patients with chronic lymphocytic leukemia (CLL) (n=81) and age-matched healthy volunteers (HVs; n=21) using 16S ribosomal RNA next-generation sequencing. Changes in both oral and gut microbiome structures were identified, with a high abundance of Proteobacteria and depletion of Bacteroidetes in CLL as compared to HVs. Oral and stool samples of patients with CLL revealed a significant change in the abundance of short-chain fatty acid-producing genera in comparison with HVs. Furthermore, the relative abundance of oral and intestine Bacteroidetes was significantly decreased in patients with CLL with negative prognostic features, including unmutated immunoglobulin heavy chain gene (IGHV). Notably, an increased abundance of gut Firmicutes was found to be associated with high expression of CD38. Finally, the present study suggested the log Firmicutes/Bacteroidota ratio as a novel intestinal microbiome signature associated with a shorter time to first treatment in individuals with CLL. The findings indicate that oral and gut microbial diversity in CLL might point to the inflammatory-related modulation of the clinical course of the disease.

Primary cutaneous lymphoproliferations in the gray zone between marginal zone lymphoma and CD4+ small/medium T-cell lymphoproliferative disease

BACKGROUND

Primary cutaneous marginal zone lymphoma (PCMZL) and primary cutaneous CD4+ small/medium T-cell lymphoproliferative disease (CD4+ TLPD) are two distinct entities with excellent prognosis; however, they show profound clinical and histopathological similarities, leading to differential diagnostic uncertainty.

AIMS

Our aim was to review and reanalyze cases of primary cutaneous lymphoproliferations diagnosed at Semmelweis University, featuring characteristics of PCMZL and CD4+ TLPD.

MATERIALS AND METHODS

Cutaneous lymphoma biopsy specimens between 2018 and 2022 were collected and re-evaluated. Medical history, clinical picture, imaging, and laboratory findings were collected. Immunohistochemical staining for CD20, CD3, BCL6, CD10, PD1, CD3, CD4, CD8, and PCR tests for IGH, IGK, TCRB, and TCRG were repeated in selected cases.

RESULTS

Among 55 cases diagnosed as PCMZL (16) or CD4+ TLPD (39), 3 patients had been diagnosed with both LPDs at different time points of their disease course. Four additional patients were identified with single lesions featuring overlapping histopathological characteristics of both LPDs and both monoclonal IGH and TCR rearrangements. All patients are currently in complete remission with local treatment.

CONCLUSION

We propose that besides the overlapping histopathological, molecular, and clinical features, the subsequent appearance of PCMZL and CD4+ TLPD in a short timeframe in the same patients may suggest a common pathogenic background.

Association of both BCL2 positive and negative follicular lymphoma to clasical Hodgkin lymphoma and/or gray zone lymphoma

We present a series of 9 follicular lymphomas that progressed/transformed into classical Hodgkin lymphoma (CHL). Three cases of CHL showed a syncytial pattern (SCHL) making the differential diagnosis to Gray zone lymphoma (GZL) challenging. None of these three cases presented in the mediastinum. Based in all molecular data analyzed (BCL2/BCL6 FISH studies, IgH PCR and TNGS with a customized gene panel) we did find clonal relationship between the BCL2-positive FL cases and their CHL components in all cases. The three SCHL/GZL cases showed an activated phenotype according to Hans algorithm, presented the t(14; 18)(q32; q21), two out of three showed B cell markers and all expressed CD30 and p53. Interestingly, we identified three BCL2-negative FL cases with a further diagnosis of CHL expanding the spectrum of these association. In one of these three cases a different mutational profile was found in both the FL and the CHL components. All this data together suggests that CHL associated to BCL2-positive FL could be originated in a common progenitor cell (CPC) that give rise to both FL and CHL, acquiring this last component further genetic events in a linear fashion. On the other hand, no clonal relationship between CHL and BCL2-negative FL could be found, suggesting a fortuity association. Nevertheless, ample series of cases studied with more sensitive techniques are needed to confirm our hypothesis.

Assessing T-cell receptor clonality by next-generation sequencing in atypical cutaneous lymphoid infiltrates and cutaneous T-cell lymphoma: A scoping review

The diagnosis of cutaneous T-cell lymphoma (CTCL) remains challenging. Demonstration of a clonal T-cell population using T-cell receptor (TCR) gene rearrangement studies by next-generation sequencing (NGS) has been explored in several studies. This review summarizes the current literature on NGS-based sequencing methods for the assessment of TCR clonality in the evaluation of atypical cutaneous lymphoid infiltrates and CTCL on behalf of the American Society of Dermatopathology Appropriate Use Criteria Committee (lymphoproliferative subgroup). PubMed was searched for relevant articles, including CTCL and NGS, for clonality from 1967 to 2022. Thirteen studies were included in the analysis. The skin was the most commonly assayed compartment with TCR NGS. Sensitivity for TCR NGS in the skin ranged between 69% and 100%, compared to 44%-72% for polymerase chain reaction (PCR)-capillary electrophoresis. Specificity for TCR NGS in the skin ranged from 86% to 100%, compared to 77%-88% for PCR capillary electrophoresis. TCR NGS was also reported to have potential prognostic value in CTCL and can also be used to detect relapse and/or minimal residual disease after treatment.

Aberrant p53 immunostaining patterns in breast carcinoma of no special type strongly correlate with presence and type of TP53 mutations

Recent studies have revealed an association between TP53 mutations and endocrine resistance in hormone receptor-positive, HER2-negative breast cancer (HR + HER2 -BC). Aberrant p53 immunostaining (IHC) patterns may provide a surrogate marker for TP53 mutations. Building upon a ternary algorithm of aberrant staining patterns, this study evaluates the reliability of p53 IHC as screening tool for TP53 mutations in BC (NST). Furthermore, it describes the histopathological and molecular characteristics of TP53-mutated cases, along with the mutational status of PIK3CA. This study comprised 131 early-stage, node-negative BCs with available core biopsies and resection specimens. Cases were categorized as follows: HR + HER2 - (85 cases), HER2 + (21 cases) and triple negative (TN, 25 cases). Aberrant IHC staining patterns for p53 were defined as overexpression (OE), complete absence (CA) and cytoplasmic (CY). In addition, targeted sequencing of TP53 and PIK3CA genes was performed. TP53 mutations were identified in 53 of 126 cases (42.1%). Within HR + HER2 - cases, TP53 mutations were found in 17 of 80 cases (21.3%). IHC accurately predicted TP53 mutation in 96.2% of cases with a specificity of 100%. Additionally, there was a significant agreement between missense mutations and OE, as well as between truncating mutations and CA (κ 73% and 76%). CY was observed in two TN cases with truncating mutations within the nuclear localization signalling domain of p53. TP53-mutated cases exhibited higher grade, greater nuclear pleomorphism and higher Ki-67 proliferation index and were associated with the PIK3CA wild-type status (p < 0.001). p53 IHC may provide a useful screening tool for identifying TP53-mutated BC of NST.