The Clinical Relevance of the EPH/Ephrin Signaling Pathway in Pediatric Solid and Hematologic Malignancies.

Pediatric neoplasms represent a complex group of malignancies that pose unique challenges in terms of diagnosis, treatment, and understanding of the underlying molecular pathogenetic mechanisms. Erythropoietin-producing hepatocellular receptors (EPHs), the largest family of receptor tyrosine kinases and their membrane-tethered ligands, ephrins, orchestrate short-distance cell-cell signaling and are intricately involved in cell-pattern morphogenesis and various developmental processes. Unraveling the role of the EPH/ephrin signaling pathway in the pathophysiology of pediatric neoplasms and its clinical implications can contribute to deciphering the intricate landscape of these malignancies. The bidirectional nature of the EPH/ephrin axis is underscored by emerging evidence revealing its capacity to drive tumorigenesis, fostering cell-cell communication within the tumor microenvironment. In the context of carcinogenesis, the EPH/ephrin signaling pathway prompts a reevaluation of treatment strategies, particularly in pediatric oncology, where the modest progress in survival rates and enduring treatment toxicity necessitate novel approaches. Molecularly targeted agents have emerged as promising alternatives, prompting a shift in focus. Through a nuanced understanding of the pathway's intricacies, we aim to lay the groundwork for personalized diagnostic and therapeutic strategies, ultimately contributing to improved outcomes for young patients grappling with neoplastic challenges.

γδ T Cells: A Game Changer in the Future of Hepatocellular Carcinoma Immunotherapy.

Hepatocellular carcinoma (HCC) remains a global health challenge with limited treatment options and a poor prognosis for advanced-stage patients. Recent advancements in cancer immunotherapy have generated significant interest in exploring novel approaches to combat HCC. One such approach involves the unique and versatile subset of T cells known as γδ T cells. γδ T cells represent a distinct subset of T lymphocytes that differ from conventional αß T cells in terms of antigen recognition and effector functions. They play a crucial role in immunosurveillance against various malignancies, including HCC. Recent studies have demonstrated that γδ T cells can directly recognize and target HCC cells, making them an attractive candidate for immunotherapy. In this article, we aimed to explore the role exerted by γδ T cells in the context of HCC. We investigate strategies designed to maximize the therapeutic effectiveness of these cells and examine the challenges and opportunities inherent in applying these research findings to clinical practice. The potential to bring about a revolutionary shift in HCC immunotherapy by capitalizing on the unique attributes of γδ T cells offers considerable promise for enhancing patient outcomes, warranting further investigation.

Unraveling the Role of the NLRP3 Inflammasome in Lymphoma: Implications in Pathogenesis and Therapeutic Strategies.

Inflammasomes are multimeric protein complexes, sensors of intracellular danger signals, and crucial components of the innate immune system, with the NLRP3 inflammasome being the best characterized among them. The increasing scientific interest in the mechanisms interconnecting inflammation and tumorigenesis has led to the study of the NLRP3 inflammasome in the setting of various neoplasms. Despite a plethora of data regarding solid tumors, NLRP3 inflammasome's implication in the pathogenesis of hematological malignancies only recently gained attention. In this review, we investigate its role in normal lymphopoiesis and lymphomagenesis. Considering that lymphomas comprise a heterogeneous group of hematologic neoplasms, both tumor-promoting and tumor-suppressing properties were attributed to the NLRP3 inflammasome, affecting neoplastic cells and immune cells in the tumor microenvironment. NLRP3 inflammasome-related proteins were associated with disease characteristics, response to treatment, and prognosis. Few studies assess the efficacy of NLRP3 inflammasome therapeutic targeting with encouraging results, though most are still at the preclinical level. Further understanding of the mechanisms regulating NLRP3 inflammasome activation during lymphoma development and progression can contribute to the investigation of novel treatment approaches to cover unmet needs in lymphoma therapeutics.

Metformin in Esophageal Carcinoma: Exploring Molecular Mechanisms and Therapeutic Insights.

Esophageal cancer (EC) remains a formidable malignancy with limited treatment options and high mortality rates, necessitating the exploration of innovative therapeutic avenues. Through a systematic analysis of a multitude of studies, we synthesize the diverse findings related to metformin's influence on EC. This review comprehensively elucidates the intricate metabolic pathways and molecular mechanisms through which metformin may exert its anti-cancer effects. Key focus areas include its impact on insulin signaling, AMP-activated protein kinase (AMPK) activation, and the mTOR pathway, which collectively contribute to its role in mitigating esophageal cancer progression. This review critically examines the body of clinical and preclinical evidence surrounding the potential role of metformin, a widely prescribed anti-diabetic medication, in EC management. Our examination extends to the modulation of inflammation, oxidative stress and angiogenesis, revealing metformin's potential as a metabolic intervention in esophageal cancer pathogenesis. By consolidating epidemiological and clinical data, we assess the evidence that supports metformin's candidacy as an adjuvant therapy for esophageal cancer. By summarizing clinical and preclinical findings, our review aims to enhance our understanding of metformin's role in EC management, potentially improving patient care and outcomes.

Meeting at the Crossroad between Obesity and Hepatic Carcinogenesis: Unique Pathophysiological Pathways Raise Expectations for Innovative Therapeutic Approaches.

The escalating global prevalence of obesity and its intricate association with the development of hepatocellular carcinoma (HCC) pose a substantial challenge to public health. Obesity, acknowledged as a pervasive epidemic, is linked to an array of chronic diseases, including HCC, catalyzing the need for a comprehensive understanding of its molecular underpinnings. Notably, HCC has emerged as a leading malignancy with rising incidence and mortality. The transition from viral etiologies to the prominence of metabolic dysfunction-associated fatty liver disease (MAFLD)-related HCC underscores the urgent need to explore the intricate molecular pathways linking obesity and hepatic carcinogenesis. This review delves into the interwoven landscape of molecular carcinogenesis in the context of obesity-driven HCC while also navigating using the current therapeutic strategies and future prospects for combating obesity-related HCC. We underscore the pivotal role of obesity as a risk factor and propose an integrated approach encompassing lifestyle interventions, pharmacotherapy, and the exploration of emerging targeted therapies. As the obesity-HCC nexus continues to challenge healthcare systems globally, a comprehensive understanding of the intricate molecular mechanisms and innovative therapeutic strategies is imperative to alleviate the rising burden of this dual menace.

Clinical picture, outcome and predictive factors of lymphoma in primary Sjögren's syndrome: results from a harmonized dataset (1981-2021).

OBJECTIVES: Primary Sjögren's Syndrome (pSS) carries the highest risk for non-Hodgkin's lymphoma (NHL) development among systemic autoimmune diseases. However, the paucity of data on the long-term survival of those patients and the lack of established predictors for each lymphoma histologic subtype prompted our present study. METHODS: We retrospectively analysed 121 patients diagnosed with NHL according to the WHO classification criteria. All patients fulfilled the 2016 ACR-EULAR classification criteria for pSS. Cumulative clinical, laboratory, radiologic, treatment regimens and histologic data were recorded, harmonized and analysed. Overall survival (OS) and event-free survival (EFS) curves were calculated. A mucosa-associated lymphoid tissue lymphoma (MALTL) prediction model was developed by applying innovative data-driven analysis of clinical features present at the time of pSS diagnosis. RESULTS: MALTLs constituted the majority of lymphomas (92/121, 76.0%) followed by diffuse large B-cell lymphomas (DLBCL) (11/121, 9.0%) and nodal marginal zone lymphomas (NMZL) (8/121, 7%). MALTLs show salivary glands localization, limited disease and often bone marrow and nodal involvement. The 10-year OS and EFS rates were 79% and 45.5% for MALTLs, 40.9% and 24.2% for DLBCL and 46% and 31% for NMZL. Cryoglobulinemia, focus score and the total EULAR SS Disease Activity Index (ESSDAI) composite index at pSS diagnosis were proven independent MALTL predictors. Even though MALTLs have a comparatively good survival outlook, they are accompanied by frequent events throughout their clinical course. CONCLUSIONS: Common features of pSS, present at diagnosis, can predict future lymphomagenesis meriting a more intensive follow-up plan.

The clinical phenotype of primary Sjögren's syndrome patients with lymphadenopathy.

OBJECTIVES: Previous cohort studies have shown that around 10% of patients with primary Sjögren's syndrome (pSS) develop lymphadenopathy during their disease course. However, no studies have described their clinical phenotype. The present study aims to describe the clinical manifestations and laboratory findings of pSS patients presenting long-standing lymphadenopathy. METHODS: From a total of 1234 consecutive pSS patients fulfilling the 2016 ACR-EULAR criteria, those with stable lymphadenopathy unrelated to lymphoma were identified (lymphadenopathy group). Their clinical data were collected and compared with 2 control groups: a) the remaining unmatched pSS patients without lymphadenopathy (unmatched non-lymphadenopathy group) and b) pSS patients without lymphadenopathy matched for age, sex, and disease duration, in an approximately 1:1 ratio (matched non-lymphadenopathy group). RESULTS: One hundred and sixty-five (13.37%) patients presented persistent, stable lymphadenopathy. They were characterised by younger age at both pSS onset and diagnosis, and by shorter disease duration. Compared to the unmatched nonlymphadenopathy group, patients with lymphadenopathy had more frequently salivary gland enlargement (p<0.001), higher focus score at first salivary gland biopsy (p=0.017), palpable purpura (p<0.001), peripheral nervous system involvement (p=0.012), glomerulonephritis (p<0.001), and leukopenia (p<0.001), while the results of the matched comparison were similar. Regarding the serological profile, the comparison with the unmatched group demonstrated higher frequency of ANA (p=0.013), anti-Ro/SSA (p=0.001), and anti-La/SSB (p<0.001) positivity for the lymphadenopathy group, while in the matched comparison only higher rates of anti-Ro/SSA positivity (p=0.002) remained statistically significant. CONCLUSIONS: pSS patients presenting non-lymphoma related stable lymphadenopathy constitute a subgroup of younger individuals with B-cell hyperactivation.

COVID-19 infection among autoimmune rheumatic disease patients: Data from an observational study and literature review.

The impact of SARS-CoV-2 infection in patients with autoimmune/auto-inflammatory rheumatic diseases (AARD) under immunomodulatory treatment has been a focus of interest during the COVID-19 pandemic. In this observational study, demographic data, disease related features and comorbidities, COVID-19 manifestations and outcome as well as antibody responses to SARS-CoV-2 were recorded among 77 consecutive patients with underlying AARD infected by SARS-CoV-2. Analysis of data was performed using univariate and multivariate models. Most patients (68.8%) had a mild COVID-19 course. The predominant clinical manifestations were fatigue (58.4%), low grade fever (45.4%) and upper respiratory tract symptoms (68.8%). About a quarter of patients required hospitalization (23.3%) and the mortality rate was 1.3%. Regarding COVID-19 severity, prior treatment with corticosteroids, mycophenolate mofetil or rituximab was more common in patients who developed a more serious disease course (60.0 vs 29.9%, p = 0.003, 40.0 vs 7.5%, p = 0.003, 10.0 vs 0.0%, p = 0.009, respectively). When disease related features and comorbidities were considered in multivariate models, older age and lung disease in the context of the AARD were found to be independent predictive factors for hospitalization (OR [95%]: 1.09 [1.03-1.15] and 6.43 [1.11-37.19]). Among COVID-19 related features, patients with shortness of breath and high-grade fever were more likely to get hospitalized (OR [95%]: 7.06 [1.36-36.57], 12.04 [2.96-48.86]), while anosmia was independently associated with lower hospitalization risk (OR [95%]: 0.09 [0.01-0.99]). Though the majority of AARD patients displayed a mild COVID-19 course, certain underlying disease features and COVID-19 related manifestations should prompt alertness for the physician to identify patients with AARD at high risk for severe COVID-19 and need for hospitalization.

A prospective multicenter study assessing humoral immunogenicity and safety of the mRNA SARS-CoV-2 vaccines in Greek patients with systemic autoimmune and autoinflammatory rheumatic diseases.

OBJECTIVES: To investigate humoral responses and safety of mRNA SARS-CoV-2 vaccines in systemic autoimmune and autoinflammatory rheumatic disease (SAARD) patients subjected or not to treatment modifications during vaccination. METHODS: A nationwide, multicenter study, including 605 SAARD patients and 116 controls, prospectively evaluated serum anti-SARS-CoV-2 S1-protein IgG antibody titers, side-effects, and disease activity, one month after complete vaccination, in terms of distinct treatment modification strategies (none, partial and extended modifications). Independent risk factors associated with hampered humoral responses were identified by data-driven multivariable logistic regression analysis. RESULTS: Patients with extended treatment modifications responded to vaccines similarly to controls as well as SAARD patients without immunosuppressive therapy (97.56% vs 100%, p = 0.2468 and 97.56% vs 97.46%, p > 0.9999, respectively). In contrast, patients with partial or without therapeutic modifications responded in 87.50% and 84.50%, respectively. Furthermore, SAARD patients with extended treatment modifications developed higher anti-SARS-CoV-2 antibody levels compared to those without or with partial modifications (median:7.90 vs 7.06 vs 7.1, p = 0.0003 and p = 0.0195, respectively). Mycophenolate mofetil (MMF), rituximab (RTX) and methotrexate (MTX) negatively affected anti-SARS-CoV-2 humoral responses. In 10.5% of vaccinated patients, mild clinical deterioration was noted; however, no differences in the incidence of deterioration were observed among the distinct treatment modification SAARD subgroups. Side-effects were generally comparable between SAARD patients and controls. CONCLUSIONS: In SAARD patients, mRNA SARS-CoV-2 vaccines are effective and safe, both in terms of side-effects and disease flares. Treatment with MMF, RTX and/or MTX compromises anti-SARS-CoV-2 antibody responses, which are restored upon extended treatment modifications without affecting disease activity.

Autophagy and Metabolism in Normal and Malignant Hematopoiesis.

The hematopoietic system relies on regulation of both metabolism and autophagy to maintain its homeostasis, ensuring the self-renewal and multipotent differentiation potential of hematopoietic stem cells (HSCs). HSCs display a distinct metabolic profile from that of their differentiated progeny, while metabolic rewiring from glycolysis to oxidative phosphorylation (OXPHOS) has been shown to be crucial for effective hematopoietic differentiation. Autophagy-mediated regulation of metabolism modulates the distinct characteristics of quiescent and differentiating hematopoietic cells. In particular, mitophagy determines the cellular mitochondrial content, thus modifying the level of OXPHOS at the different differentiation stages of hematopoietic cells, while, at the same time, it ensures the building blocks and energy for differentiation. Aberrations in both the metabolic status and regulation of the autophagic machinery are implicated in the development of hematologic malignancies, especially in leukemogenesis. In this review, we aim to investigate the role of metabolism and autophagy, as well as their interconnections, in normal and malignant hematopoiesis.

Akt Signaling Pathway Is Activated in the Minor Salivary Glands of Patients with Primary Sjögren's Syndrome.

Primary Sjögren's syndrome (pSS) is an autoimmune exocrinopathy of mainly the salivary and lacrimal glands associated with high prevalence of lymphoma. Akt is a phosphoinositide-dependent serine/threonine kinase, controlling numerous pathological processes, including oncogenesis and autoimmunity. Herein, we sought to examine its implication in pSS pathogenesis and related lymphomagenesis. The expression of the entire and activated forms of Akt (partially and fully activated: phosphorylated at threonine-308 (T308) and serine-473 (S473), respectively), and two of its substrates, the proline-rich Akt-substrate of 40 kDa (PRAS40) and FoxO1 transcription factor has been immunohistochemically examined in minor salivary glands (MSG) of pSS patients (n = 29; including 9 with pSS-associated lymphoma) and sicca-complaining controls (sicca-controls; n = 10). The entire and phosphorylated Akt, PRAS40, and FoxO1 molecules were strongly, uniformly expressed in the MSG epithelia and infiltrating mononuclear cells of pSS patients, but not sicca-controls. Morphometric analysis revealed that the staining intensity of the fully activated phospho-Akt-S473 in pSS patients (with or without lymphoma) was significantly higher than sicca-controls. Akt pathway activation was independent from the extent or proximity of infiltrates, as well as other disease features, including lymphoma. Our findings support that the Akt pathway is specifically activated in MSGs of pSS patients, revealing novel therapeutic targets.

Exploiting the Role of Hypoxia-Inducible Factor 1 and Pseudohypoxia in the Myelodysplastic Syndrome Pathophysiology.

Myelodysplastic syndromes (MDS) comprise a heterogeneous group of clonal hematopoietic stem (HSCs) and/or progenitor cells disorders. The established dependence of MDS progenitors on the hypoxic bone marrow (BM) microenvironment turned scientific interests to the transcription factor hypoxia-inducible factor 1 (HIF-1). HIF-1 facilitates quiescence maintenance and regulates differentiation by manipulating HSCs metabolism, being thus an appealing research target. Therefore, we examine the aberrant HIF-1 stabilization in BMs from MDS patients and controls (CTRLs). Using a nitroimidazole-indocyanine conjugate, we show that HIF-1 aberrant expression and transcription activity is oxygen independent, establishing the phenomenon of pseudohypoxia in MDS BM. Next, we examine mitochondrial quality and quantity along with levels of autophagy in the differentiating myeloid lineage isolated from fresh BM MDS and CTRL aspirates given that both phenomena are HIF-1 dependent. We show that the mitophagy of abnormal mitochondria and autophagic death are prominently featured in the MDS myeloid lineage, their severity increasing with intra-BM blast counts. Finally, we use in vitro cultured CD34+ HSCs isolated from fresh human BM aspirates to manipulate HIF-1 expression and examine its potential as a therapeutic target. We find that despite being cultured under 21% FiO2, HIF-1 remained aberrantly stable in all MDS cultures. Inhibition of the HIF-1α subunit had a variable beneficial effect in all <5%-intra-BM blasts-MDS, while it had no effect in CTRLs or in ≥5%-intra-BM blasts-MDS that uniformly died within 3 days of culture. We conclude that HIF-1 and pseudohypoxia are prominently featured in MDS pathobiology, and their manipulation has some potential in the therapeutics of benign MDS.

T cell lymphoma in the setting of Sjögren's syndrome: T cells gone bad? Report of five cases from a single centre cohort.

OBJECTIVES: To identify and record lymphomas of T cell origin in a single centre cohort of 110 Sjögren's syndrome (SS)-associated non-Hodgkin's lymphoma (NHL) patients, followed up from 1993 to June 2020. METHODS: We searched for patients diagnosed with T cell lymphoma among 110 SS-associated NHL cases. Demographic data, history of previous lymphoma, histologic subtype, lymphoma stage, treatment schedules, and response to therapy were documented. RESULTS: Among the 110 SS-associated NHL patients, we identified five NHL cases of T cell origin, all of whom were women. The median time from SS diagnosis to T cell lymphoma development was 3.25 years. They all expressed at least one adverse predictive factor for lymphoma development. Lymphoma subtypes were identified as: two peripheral T cell lymphomas not otherwise specified (NOS) lymphomas, one primary cutaneous T cell lymphoma, one T large granular lymphocyte (T-LGL) leukaemia and one angioimmunoblastic T cell lymphoma. All lymphomas were stage IV, apart from the latter case that was stage III, according to the Ann Arbor staging system. All lymphomas tested positive for T cell receptor (TCR) gamma clonal rearrangements in biopsy specimens, and two were also positive for Epstein-Barr virus-encoded RNA (EBER). Two out of five patients had previously been diagnosed with B cell lymphoma, treated with combined immunochemotherapy, and one had been previously diagnosed with lymph node benign polyclonal follicular hyperplasia. CONCLUSIONS: SS-associated T cell lymphomas constitute a minority. Treatment with anti-CD20 monoclonal antibody (mAb) and viral infections may be implicated in their pathogenesis.

PD-L1 Expression in Neoplastic and Immune Cells of Thymic Epithelial Tumors: Correlations with Disease Characteristics and HDAC Expression.

BACKGROUND: Programmed death-ligand 1 (PD-L1) expression in neoplastic and immune cells of the tumor microenvironment determines the efficacy of antitumor immunity, while it can be regulated at the epigenetic level by various factors, including HDACs. In this study, we aim to evaluate the expression patterns of PD-L1 in thymic epithelial tumors (TETs), while we attempt the first correlation analysis between PD-L1 and histone deacetylases (HDACs) expression. METHODS: Immunohistochemistry was used to evaluate the expression of PD-L1 in tumor and immune cells of 91 TETs with SP263 and SP142 antibody clones, as well as the expressions of HDCA1, -2, -3, -4, -5, and -6. RESULTS: The PD-L1 tumor proportion score (TPS) was higher, while the immune cell score (IC-score) was lower in the more aggressive TET subtypes and in more advanced Masaoka-Koga stages. A positive correlation between PD-L1 and HDAC-3, -4, and -5 cytoplasmic expression was identified. CONCLUSIONS: Higher PD-L1 expression in neoplastic cells and lower PD-L1 expression in immune cells of TETs characterizes more aggressive and advanced neoplasms. Correlations between PD-L1 and HDAC expression unravel the impact of epigenetic regulation on the expression of immune checkpoint molecules in TETs, with possible future applications in combined therapeutic targeting.

Understanding the Role of Connexins in Hepatocellular Carcinoma: Molecular and Prognostic Implications.

Connexins, a family of tetraspan membrane proteins forming intercellular channels localized in gap junctions, play a pivotal role at the different stages of tumor progression presenting both pro- and anti-tumorigenic effects. Considering the potential role of connexins as tumor suppressors through multiple channel-independent mechanisms, their loss of expression may be associated with tumorigenic activity, while it is hypothesized that connexins favor the clonal expansion of tumor cells and promote cell migration, invasion, and proliferation, affecting metastasis and chemoresistance in some cases. Hepatocellular carcinoma (HCC), characterized by unfavorable prognosis and limited responsiveness to current therapeutic strategies, has been linked to gap junction proteins as tumorigenic factors with prognostic value. Notably, several members of connexins have emerged as promising markers for assessing the progression and aggressiveness of HCC, as well as the chemosensitivity and radiosensitivity of hepatocellular tumor cells. Our review sheds light on the multifaceted role of connexins in HCC pathogenesis, offering valuable insights on recent advances in determining their prognostic and therapeutic potential.

Unraveling the Significance of EPH/Ephrin Signaling in Liver Cancer: Insights into Tumor Progression and Therapeutic Implications.

Liver cancer is a complex and challenging disease with limited treatment options and dismal prognosis. Understanding the underlying molecular mechanisms driving liver cancer progression and metastasis is crucial for developing effective therapeutic strategies. The EPH/ephrin system, which comprises a family of cell surface receptors and their corresponding ligands, has been implicated in the pathogenesis of HCC. This review paper aims to provide an overview of the current understanding of the role of the EPH/ephrin system in HCC. Specifically, we discuss the dysregulation of EPH/ephrin signaling in HCC and its impact on various cellular processes, including cell proliferation, migration, and invasion. Overall, the EPH/ephrin signaling system emerges as a compelling and multifaceted player in liver cancer biology. Elucidating its precise mechanisms and understanding its implications in disease progression and therapeutic responses may pave the way for novel targeted therapies and personalized treatment approaches for liver cancer patients. Further research is warranted to unravel the full potential of the EPH/ephrin system in liver cancer and its clinical translation.

EPH/Ephrin Signaling in Normal Hematopoiesis and Hematologic Malignancies: Deciphering Their Intricate Role and Unraveling Possible New Therapeutic Targets.

Erythropoietin-producing hepatocellular carcinoma receptors (EPHs) represent the largest family of receptor tyrosine kinases (RTKs). EPH interaction with ephrins, their membrane-bound ligands, holds a pivotal role in embryonic development, while, though less active, it is also implicated in various physiological functions during adult life. In normal hematopoiesis, different patterns of EPH/ephrin expression have been correlated with hematopoietic stem cell (HSC) maintenance and lineage-committed hematopoietic progenitor cell (HPC) differentiation, as well as with the functional properties of their mature offspring. Research in the field of hematologic malignancies has unveiled a rather complex involvement of the EPH/ephrinsignaling pathway in the pathophysiology of these neoplasms. Aberrations in genetic, epigenetic, and protein levels have been identified as possible players implicated both in tumor progression and suppression, while correlations have also been highlighted regarding prognosis and response to treatment. Initial efforts to therapeutically target the EPH/ephrin axis have been undertaken in the setting of hematologic neoplasia but are mainly confined to the preclinical level. To this end, deciphering the complexity of this signaling pathway both in normal and malignant hematopoiesis is necessary.

The Role of the Akt Signaling Pathway in Sjögren's Syndrome.

Primary Sjögren's syndrome (pSS) is a chronic autoimmune disorder with diverse clinical picture and high prevalence of B-cell non-Hodgkin lymphoma (NHL), that possibly raises from the chronic activation of B-cells. The mechanisms underlying the development of neoplasia in pSS remain elusive. Activated Akt/mTOR pathway is a uniform finding in cancer, whereas its significance in haematologic malignancies is highlighted by the plethora of inhibitors with promising therapeutic efficacy. PI3K-Akt activation has been involved in the TLR3-induced apoptosis of cultured salivary gland epithelial cells (SGECs), whereas upregulated expression of the phosphorylated ribosomal S6 protein (pS6), an end-result of PI3K signalling, has been detected in the infiltrating T and B lymphocytes at the MSG lesions of pSS patients; nevertheless, without specifying if this was mediated by the Akt/mTOR or Ras/ERK pathways. To this end, the role of Akt/mTOR pathway in pSS and associated lymphomagenesis, will be investigated by the immunohistochemical detection of the entire and phosphorylated protein forms of Akt kinase and two of its substrates, namely the FoxO1 transcription factor and the proline-rich Akt substrate of 40-kDa (PRAS40) in MSGs of pSS patients with variable histological and clinical phenotype, as well as sicca-complaining controls. Subsequently, the role of this pathway will be evaluated in in-vitro inhibition experiments, studying the effect of specific inhibitors in the phenotype, function, and interaction of SGECs and B cells. The current proposal is expected to promote the understanding of pSS pathogenesis, enlighten the mechanisms underlying related lymphomagenesis and possible therapeutic targets.