The immune microenviroment in somatotropinomas: from biology to personalized and target therapy

Genes of the "regulation of lymphocyte activation" pathway may influence immune cells infiltration in growth hormone secreting pituitary tumors

PURPOSE

The tumor microenvironment (TME) may provide a useful framework for understanding the heterogeneous behavior of growth hormone (GH) secreting pituitary adenomas. Although the interest in TME in somatotropinomas has increased exponentially over the last few decades, there is limited elucidation of its mechanisms, particularly in relation to genes expression involved in its regulation.

METHODS

A retrospective, observational, single-center study was conducted on 85 subjects: 46 patients diagnosed with acromegaly and 39 controls. After DNA extraction, clinical exome sequencing was performed and genomic alterations were detected, classified, and filtered using a dedicated bioinformatics pipeline.

RESULTS

5759 unique genetic variants were found in patients with acromegaly. 33 patients (72%) showed the presence of at least one pathogenic variant in at least one of the following genes: FANCD2, SPTA1, TYRO3, and ZNF335. The enrichment pathway analysis of mutated genes was performed and showed that these genes were included in the same genetic pathway called "regulation of lymphocyte activation" (GO:0051249). Inflammatory infiltrate was analyzed in histological samples in 26 patients. A significantly higher number of CD68 + macrophages (P-value = 0.008), a lower number of CD8 + T lymphocytes (P-value = 0.037) and a higher CD68 + macrophages/ CD8 + T-lymphocytes ratio (P-value = 0.004) were observed in patients with pathogenic variants of genes of "regulation of lymphocyte activation" pathway.

CONCLUSION

This study provides new insights into the genetic basis of the TME in somatotropinomas and suggests that genetics may influence immune cells infiltration in acromegaly.

New insights in cellular senescence: The pituitary model

Pituitary tumors are characterized by slow proliferation rates and a high prevalence within the population. The pathogenesis of these tumors remains incompletely understood, although accumulating evidence suggests that the activation of the cellular senescence program, triggered by various stressors and functioning as a brake on cellular proliferation, may contribute to their typically benign nature. Multiple mediators of the senescence response are implicated in this process. Interleukin-6 (IL-6), a proinflammatory cytokine, plays a dual role in pituitary tumor biology. It is involved in both physiological pituitary growth and the senescence-associated secretory phenotype (SASP), where it mediates paracrine-proliferative signals. In addition to its secretory functions, IL-6 has been implicated in the regulation of pituitary senescence through non-secretory mechanisms. Other factors, such as growth hormone (GH), the pituitary tumor-transforming gene (PTTG), and interactions within the tumor microenvironment, including immune cell dynamics, also contribute to the senescence observed in these tumors. This review examines the latest evidence concerning the role of senescence in pituitary tumors, with a particular focus on the contribution of IL-6 to this process.

Cancer screening in patients with acromegaly: a plea for a personalized approach and international registries

Acromegaly is a rare condition, and often diagnosis is delayed by several years, for most patients. Acromegaly is characterized by short and long-term respiratory, cardiovascular and metabolic comorbidities, with possible impact on mortality. In the last two decades, life expectancy has progressively increased in part due to a reduction in biochemically active disease, multidisciplinary treatment approaches and a reduction in complications, and the availability of new drugs. Of note, a leading cause of mortality, cardiovascular comorbidity, has been replaced by cancer(s). As such, neoplasms more frequently observed (colon, thyroid, breast, prostate, and stomach) in patients with acromegaly are receiving increased attention. Chronic exposure to increased growth hormone serum levels may contribute to an increase in the occurrence and progression of cancers. Various efforts have been made to determine the pathogenetic mechanisms involved. However, there are no clear medical-related societal agreement(s) in relation to screening methods or timing regarding neoplasm(s) diagnosis in patients with acromegaly. Additionally, independent and dependent risk factor data in patients with acromegaly is lacking. International/national registries could help lay the groundwork to better study the impact of cancer(s) in patients with acromegaly and subsequently lead to and validate the most appropriate diagnostic and therapeutic path forward.

Cytokines and chemokines modulate the growth of pituitary adenoma/neuroendocrine tumors: preliminary results of a monocenter prospective pilot study

INTRODUCTION

Cytokine and chemokines have been recognized to be involved in the progression and prognosis of pituitary adenoma/neuroendocrine tumors (PAs/PitNETs), also known as pituitary adenomas. We aim to investigate the expression of cytokine and chemokine in PAs/PitNETs, and their association with PAs/PitNETs clinical and biological behavior.

PATIENTS AND METHODS

A prospective and monocenter study was performed on 16 patients diagnosed for PAs/PitNETs. Cytokine and chemokine were detected on freshly collected PAs/PitNETs samples. Tumor infiltering immune cells were investigated on formally fixed and paraffin-embedded PAs/PitNETs samples. Clinical, biochemical, molecular and morphological data were collected from patients' medical records.

RESULT

Out of 72 patients with PAs/PitNETs that underwent surgical removal at the Neurosurgery Division of our Institution between January and June 2023, sixteen patients were enrolled in the study. Out of 42 cytokines and chemokines that we investigated, we found that the expressions of the growth-regulated oncogene (GRO)/CXCL1, thymus- and activation-regulated chemokine (TARC)/CCL17 and epidermal growth factor (EGF) were higher in invasive tumors than in not-invasive ones (respectively p = 0.01, p = 0.002 and p = 0.002). The EGF expression was higher in tumors with a MIB1 > 3% than in those with MIB1 < 3% (p = 0.014). A positive correlation was detected between the expressions of EGF and CXCL1 (p = 0.003, r: 0.7), EGF and GRO-a (p = 0.01, r:0.61), and the number of tumors infiltering CD68 + macrophages and the expression of CCL2 (p = 0.008, r = 0.695).

CONCLUSION

Our preliminary results support that in PAs/PitNETs, the cytokines and chemokines generate an immune network, that may contribute to regulating the cell proliferation and pattern of growth.

Flow cytometry immune profiling of recurrent and newly diagnosed growth hormone secreting pituitary neuroendocrine tumors: comparison of two clinical cases

Early detection of aggressive pituitary neuroendocrine tumors (PitNETs) remains challenging due to the absence of reliable markers that can predict disease progression. Aggressive tumors are typically identified through long-term observation. Tumor immune microenvironment (TIME) is crucial for understanding PitNETs' heterogeneity and identifying potential predictors of tumor aggressiveness. In this study, we analyzed immune profile of micro- and macroenvironment in two somatotropinomas (aggressive and non-aggressive) using flow cytometry. We observed lymphopenia and elevated neutrophil levels in the periphery in the patient with tumor recurrence. The aggressive TIME showed greater leukocyte infiltration, with lymphoid cells predominating over myeloid cells along with a higher proportion of CD4 + T cells over CD8 + T cells. We detected double-positive CD4 + CD8 + population, high level of regulatory T cells and a sharp increase in PD-1 + expressing T cells over six months during recurrence. In the blood of the patient with tumor recurrence, we observed reduced granule-mediated cytotoxicity of CD8 + T cells and NK-cells. In the aggressive TIME the number of effector cells producing perforin and granzyme B-both independently and simultaneously was significantly lower. The proportion of CD3-CD20- NK cells and CD3-CD56 + NK cells was low after the first recurrence but increased sharply after six months. The ratio of monocyte subpopulations in tumor differed from that in blood, with CD16 + expressing monocytes predominating in the TIME of both patients. M2 macrophages in TIME rose sharply to 60.8% over six months during recurrence. In several immunological parameters, the patient with tumor recurrence exhibited a more pronounced immunosuppressive profile.

Acromegaly and COVID-19, lessons, and new opportunities

The COVID-19 pandemic created challenges in effective management of patients with acromegaly. Specifically, with regards to timely diagnosis, delays in surgeries, and disruption(s) to routine patient care. A transition to telemedicine did help to overcome safety restrictions that were placed on in-person care. Creation of surgical safety protocols in conjunction with widespread testing for COVID-19 has also helped with the resumption of pituitary surgery cases. However, acromegaly related comorbidities including cardiovascular disease, diabetes mellitus, sleep apnea and respiratory disease, vertebral fractures, and hypopituitarism, may increase the risk of a more severe COVID-19 infection course. Of note and to date, no negative trends in COVID-19 related outcomes have been reported in patients with acromegaly. Nevertheless, anxiety and depression rates in patients with acromegaly are higher than those in the general population. More studies are needed to assess the true impact of the COVID-19 pandemic on morbidity, mortality, and neuropsychiatric health of patients with acromegaly.

Immunological signatures and predictive biomarkers for first-generation somatostatin receptor ligand resistance in Acromegaly

PURPOSE

Predicting resistance to first-generation Somatostatin Receptor Ligands (fg-SRL) in Acromegaly patients remains an ongong challenge. Tumor-associated immune components participate in various pathological processes, including drug-resistance. We aimed to identify the immune components involved in resistance of fg-SRL, and to investigate biomarkers that can be targeted to treat those drug-resistant Acromegaly.

METHODS

We conducted a retrospective study involving 35 Acromegaly patients with somatotropinomas treated postoperatively with fg-SRL. Gathering clinicopathological data, SSTR2 expression, and immunological profiles, we utilized univariate, binary logistic regression, and ROC analyses to assess their predictive roles in fg-SRL resistance. Spearman correlation analysis further examined interactions among interested characteristics.

RESULTS

19 patients (54.29%) exhibited resistance to postoperative fg-SRL. GH level at diagnosis, preoperative tumor volume, T2WI-MRI intensity, granularity, PD-L1, SSTR2, and CD8 + T cell infiltration showed association with clinical outcomes of fg-SRL. Notably, T2WI-MRI hyperintensity, PD-L1-IRS > 7, CD8 + T cell infiltration < 14.8/HPF, and SSTR2-IRS < 5.4 emerged as reliable predictors for fg-SRL resistance. Correlation analysis highlighted a negative relationship between PD-L1 expression and CD8 + T cell infiltration, while showcasing a positive correlation with preoperative tumor volume of somatotropinomas. Additionally, 5 patients with fg-SRL resistance underwent re-operation were involved. Following fg-SRL treatment, significant increases in PD-L1 and SSTR5 expression were observed, while SSTR2 expression decreased in somatotropinoma.

CONCLUSION

PD-L1 expression and CD8 + T cell infiltration, either independently or combined with SSTR2 expression and T2WI-MRI intensity, could form a predictive model guiding clinical decisions on fg-SRL employment. Furthermore, targeting PD-L1 through immunotherapy and embracing second-generations of SRL with higher affinity to SSTR5 represent promising strategies to tackle fg-SRL resistance in somatotropinomas.

The Multibiomarker Acro-TIME Score Predicts fg-SRLs Response: Preliminary Results of a Retrospective Acromegaly Cohort

CONTEXT

The prompt control of acromegaly is a primary treatment aim for reducing related disease morbidity and mortality. First-generation somatostatin receptor ligands (fg-SRLs) are the cornerstone of medical therapies. A non-negligible number of patients do not respond to this treatment. Several predictors of fg-SRL response were identified, but a comprehensive prognostic model is lacking.

OBJECTIVE

We aimed to design a prognostic model based on clinical and biochemical parameters, and pathological features, including data on immune tumor microenvironment.

METHODS

A retrospective, monocenter, cohort study was performed on 67 medically naïve patients with acromegaly. Fifteen clinical, pathological, and radiological features were collected and analyzed as independent risk factors of fg-SRLs response, using univariable and multivariable logistic regression analyses. A stepwise selection method was applied to identify the final regression model. A nomogram was then obtained.

RESULTS

Thirty-seven patients were fg-SRLs responders. An increased risk to poor response to fg-SRLs were observed in somatotropinomas with absent/cytoplasmatic SSTR2 expression (OR 5.493 95% CI 1.19-25.16, P = .028), with low CD68+/CD8+ ratio (OR 1.162, 95% CI 1.01-1.33, P = .032). Radical surgical resection was associated with a low risk of poor fg-SRLs response (OR 0.106, 95% CI 0.025-0.447 P = .002). The nomogram obtained from the stepwise regression model was based on the CD68+/CD8+ ratio, SSTR2 score, and the persistence of postsurgery residual tumor and was able to predict the response to fg-SRLs with good accuracy (area under the curve 0.85).

CONCLUSION

Although our predictive model should be validated in prospective studies, our data suggest that this nomogram may represent an easy to use tool for predicting the fg-SRL outcome early.

From Genes to Therapy: Pituitary Adenomas in the Era of Precision Medicine

This review presents a comprehensive analysis of pituitary adenomas, a type of brain tumor with diverse behaviors and complexities. We cover various treatment approaches, including surgery, radiotherapy, chemotherapy, and their integration with newer treatments. Key to the discussion is the role of biomarkers in oncology for risk assessment, diagnosis, prognosis, and the monitoring of pituitary adenomas. We highlight advances in genomic, epigenomic, and transcriptomic analyses and their contributions to understanding the pathogenesis and molecular pathology of these tumors. Special attention is given to the molecular mechanisms, including the impact of epigenetic factors like histone modifications, DNA methylation, and transcriptomic changes on different subtypes of pituitary adenomas. The importance of the tumor immune microenvironment in tumor behavior and treatment response is thoroughly analyzed. We highlight potential breakthroughs and innovations for a more effective management and treatment of pituitary adenomas, while shedding light on the ongoing need for research and development in this field to translate scientific knowledge into clinical advancements, aiming to improve patient outcomes.

Role of Tumor Microenvironment in Pituitary Neuroendocrine Tumors: New Approaches in Classification, Diagnosis and Therapy

Adenohypophysal pituitary tumors account for 10-15% of all intracranial tumors, and 25-55% display signs of invasiveness. Nevertheless, oncology still relies on histopathological examination to establish the diagnosis. Considering that the classification of pituitary tumors has changed significantly in recent years, we discuss the definition of aggressive and invasive tumors and the latest molecular criteria used for classifying these entities. The pituitary tumor microenvironment (TME) is essential for neoplastic development and progression. This review aims to reveal the impact of TME characteristics on stratifying these tumors in view of finding appropriate therapeutic approaches. The role of the pituitary tumor microenvironment and its main components, non-tumoral cells and soluble factors, has been addressed. The variable display of different immune cell types, tumor-associated fibroblasts, and folliculostellate cells is discussed in relation to tumor development and aggressiveness. The molecules secreted by both tumoral and non-tumoral cells, such as VEGF, FGF, EGF, IL6, TNFα, and immune checkpoint molecules, contribute to the crosstalk between the tumor and its microenvironment. They could be considered potential biomarkers for diagnosis and the invasiveness of these tumors, together with emerging non-coding RNA molecules. Therefore, assessing this complex network associated with pituitary neuroendocrine tumors could bring a new era in diagnosing and treating this pathology.

Aggressive PitNETs and Potential Target Therapies: A Systematic Review of Molecular and Genetic Pathways

Recently, advances in molecular biology and bioinformatics have allowed a more thorough understanding of tumorigenesis in aggressive PitNETs (pituitary neuroendocrine tumors) through the identification of specific essential genes, crucial molecular pathways, regulators, and effects of the tumoral microenvironment. Target therapies have been developed to cure oncology patients refractory to traditional treatments, introducing the concept of precision medicine. Preliminary data on PitNETs are derived from preclinical studies conducted on cell cultures, animal models, and a few case reports or small case series. This study comprehensively reviews the principal pathways involved in aggressive PitNETs, describing the potential target therapies. A search was conducted on Pubmed, Scopus, and Web of Science for English papers published between 1 January 2004, and 15 June 2023. 254 were selected, and the topics related to aggressive PitNETs were recorded and discussed in detail: epigenetic aspects, membrane proteins and receptors, metalloprotease, molecular pathways, PPRK, and the immune microenvironment. A comprehensive comprehension of the molecular mechanisms linked to PitNETs' aggressiveness and invasiveness is crucial. Despite promising preliminary findings, additional research and clinical trials are necessary to confirm the indications and effectiveness of target therapies for PitNETs.

Tumour microenvironment and pituitary tumour behaviour

The pituitary tumour microenvironment encompasses a spectrum of non-tumoural cells, such as immune, stromal or endothelial cells, as well as enzymes and signalling peptides like cytokines, chemokines and growth factors, which surround the tumour cells and may influence pituitary tumour behaviour and tumourigenic mechanisms. Recently, there has been intensive research activity in this field describing various pituitary tumour-infiltrating immune and stromal cell subpopulations, and immune- and microenvironment-related pathways. Key changes in oncological therapeutic avenues resulted in the recognition of pituitary as a target of adverse events for patients treated with immune checkpoint regulators. However, these phenomena can be turned into therapeutic advantage in severe cases of pituitary tumours. Therefore, unravelling the pituitary tumour microenvironment will allow a better understanding of the biology and behaviour of pituitary tumours and may provide further developments in terms of diagnosis and management of patients with aggressively growing or recurrent pituitary tumours.