The Role of Activation of PI3K/AKT/mTOR and RAF/MEK/ERK Pathways in Aggressive Pituitary Adenomas-New Potential Therapeutic Approach-A Systematic Review.

Pituitary tumors (PT) are mostly benign, although occasionally they demonstrate aggressive behavior, invasion of surrounding tissues, rapid growth, resistance to conventional treatments, and multiple recurrences. The pathogenesis of PT is still not fully understood, and the factors responsible for its invasiveness, aggressiveness, and potential for metastasis are unknown. RAF/MEK/ERK and mTOR signaling are significant pathways in the regulation of cell growth, proliferation, and survival, its importance in tumorigenesis has been highlighted. The aim of our review is to determine the role of the activation of PI3K/AKT/mTOR and RAF/MEK/ERK pathways in the pathogenesis of pituitary tumors. Additionally, we evaluate their potential in a new therapeutic approach to provide alternative therapies and improved outcomes for patients with aggressive pituitary tumors that do not respond to standard treatment. We perform a systematic literature search using the PubMed, Embase, and Scopus databases (search date was 2012-2023). Out of the 529 screened studies, 13 met the inclusion criteria, 7 related to the PI3K/AKT/mTOR pathway, and 7 to the RAF/MEK/ERK pathway (one study was used in both analyses). Understanding the specific factors involved in PT tumorigenesis provides opportunities for targeted therapies. We also review the possible new targeted therapies and the use of mTOR inhibitors and TKI in PT management. Although the RAF/MEK/ERK and PI3K/AKT/mTOR pathways play a pivotal role in the complex signaling network along with many interactions, further research is urgently needed to clarify the exact functions and the underlying mechanisms of these signaling pathways in the pathogenesis of pituitary adenomas and their role in its invasiveness and aggressive clinical outcome.

Clinical, Biochemical, and Sonographic Factors Influencing Performance of Parathormone Washout Measurement vs. 99mTc-MIBI Scintigraphy in the Preoperative Diagnostics of Parathyroid Adenomas.

The purpose of the study was to assess the clinical, biochemical, and sonographic factors influencing the performance of parathormone washout measurement (PTHw) vs. MIBI in the preoperative localization of parathyroid adenoma (PA). The studied group consisted of 39 patients with primary or tertiary hyperparathyroidism. The measurement of PTH concentrations was performed using an electro-chemiluminescence immunoassay. Scintigraphic localization of PA was carried out using dual-tracer planar neck scintigraphy, using 74 MBq 99mTc-pertechnetate and 740 MBq of 99mTc-MIBI. MIBI was unambiguously positive in 74% of patients. Among patients with negative or inconclusive MIBI, 90% had a positive PTHw result. Among patients with negative PTHw, two out of three had a positive MIBI result. The PTHw of lesions <10 mm in their largest diameter yielded positive results in 95%, compared to 75% for MIBI. For lesions ≥10 mm in largest diameter, 88% were visualised using MIBI. In conclusion, PTHw is a highly effective, easy, quick, safe, and relatively cheap procedure which might be considered for PA localisation, especially in patients with lesions presenting typical ultrasound features and a size below 10 mm. MIBI remains a useful procedure in specialized centres, particularly for patients in whom PTHw failed, larger lesions, and in cases of the ectopic location of PA.

Clinical Implications of mTOR Expression in Papillary Thyroid Cancer-A Systematic Review.

Papillary thyroid cancer (PTC) comprises approximately 80% of all thyroid malignancies. Although several etiological factors, such as age, gender, and irradiation, are already known to be involved in the development of PTC, the genetics of cancerogenesis remain undetermined. The mTOR pathway regulates several cellular processes that are critical for tumorigenesis. Activated mTOR is involved in the development and progression of PTC. Therefore, we performed a systematic review of papers studying the expression of the mTOR gene and protein and its relationship with PTC risk and clinical outcome. A systematic literature search was performed using PubMed, Embase, and Scopus databases (the search date was 2012-2022). Studies investigating the expression of mTOR in the peripheral blood or tissue of patients with PTC were deemed eligible for inclusion. Seven of the 286 screened studies met the inclusion criteria for mTOR gene expression and four for mTOR protein expression. We also analyzed the data on mTOR protein expression in PTC. We analyzed the association of mTOR expression with papillary thyroid cancer clinicopathological features, such as the TNM stage, BRAF V600E mutation, sex distribution, lymph node and distant metastases, and survival prognosis. Understanding specific factors involved in PTC tumorigenesis provides opportunities for targeted therapies. We also reviewed the possible new targeted therapies and the use of mTOR inhibitors in PTC. This topic requires further research with novel techniques to translate the achieved results to clinical application.

[99mTc]Tc-DB15 in GRPR-Targeted Tumor Imaging with SPECT: From Preclinical Evaluation to the First Clinical Outcomes.

Diagnostic imaging and radionuclide therapy of prostate (PC) and breast cancer (BC) using radiolabeled gastrin-releasing peptide receptor (GRPR)-antagonists represents a promising approach. We herein propose the GRPR-antagonist based radiotracer [99mTc]Tc-DB15 ([99mTc]Tc-N4-AMA-DGA-DPhe6,Sar11,LeuNHEt13]BBN(6-13); N4: 6-carboxy-1,4,8,11-tetraazaundecane, AMA: aminomethyl-aniline, DGA: diglycolic acid) as a new diagnostic tool for GRPR-positive tumors applying SPECT/CT. The uptake of [99mTc]Tc-DB15 was tested in vitro in mammary (T-47D) and prostate cancer (PC-3) cells and in vivo in T-47D or PC-3 xenograft-bearing mice as well as in BC patients. DB15 showed high GRPR-affinity (IC50 = 0.37 ± 0.03 nM) and [99mTc]Tc-DB15 strongly bound to the cell-membrane of T-47D and PC-3 cells, according to a radiolabeled antagonist profile. In mice, the radiotracer showed high and prolonged GRPR-specific uptake in PC-3 (e.g., 25.56 ± 2.78 %IA/g vs. 0.72 ± 0.12 %IA/g in block; 4 h pi) and T-47D (e.g., 15.82 ± 3.20 %IA/g vs. 3.82 ± 0.30 %IA/g in block; 4 h pi) tumors, while rapidly clearing from background. In patients with advanced BC, the tracer could reveal several bone and soft tissue metastases on SPECT/CT. The attractive pharmacokinetic profile of [99mTc]DB15 in mice and its capability to target GRPR-positive BC lesions in patients highlight its prospects for a broader clinical use, an option currently being explored by ongoing clinical studies.

Immunohistochemical analysis of ghrelin expression in various types of adrenal tumors.

INTRODUCTION: Ghrelin, originally isolated from the endocrine cells of the gastric mucosa, is also expressed in many peripheral tissues, including normal adrenals and adrenocortical tumors. It was shown that ghrelin stimulates proliferation and inhibits apoptosis of adrenocortical cells. In the current study, we compared ghrelin expression at the protein level in various adrenal tumors. We analyzed whether immunoreactive ghrelin could be considered as a potential marker for different types of adrenal tumors. MATERIAL AND METHODS: Study was carried out on 200 adrenal specimens arranged on microscope slide in tissue microarray format. We performed standardized immunohistochemical reactions with semiquantitative reaction intensity measurements. RESULTS: At the protein level, the expression of ghrelin was significantly reduced in adrenocortical adenocarcinoma in relation to the control group and pheochromocytoma as well as cancer-adjacent normal adrenal tissue. In contrast, a relatively high ghrelin expression was found in pheochromocytoma compared to all analyzed groups, with the exception of cancer-adjacent normal adrenal tissue. CONCLUSIONS: The ghrelin expression profile at the protein level may be associated with the type of adrenal tumor. In this context, our results suggest that adrenal immunoreactive ghrelin may be considered as a sensitive and specific marker for differentiating adrenocortical carcinoma from adrenocortical adenoma and pheochromocytoma.

Predictive factors determining incomplete response to radioiodine therapy in patients with differentiated thyroid cancer.

BACKGROUND: Although differentiated thyroid cancer (DTC) has relatively favorable course, factors predicting the course of the disease are intensively searched. The aim of the study was to identify the clinical factors determining incomplete response to radioiodine therapy in patients with DTC. METHODS: We retrospectively analyzed 385 consecutive patients with DTC treated and followed-up at a single tertiary reference center. We investigated clinical factors detectable during first hospitalization 3-6 months following total thyroidectomy due to DTC, which may serve as prognostic factors determining response to DTC therapy in a long-term follow-up. RESULTS: Stimulated thyroglobulin (sTg) was the only parameter significantly correlated with the cumulative radioiodine activity (r=0.247, P<0.001). The need for repeated radioiodine administration (≥3 doses) was best predictable on the basis of sTg concentration assessed at the moment of qualification to radioiodine therapy (P=0.003). Predictive value of the sTg for incomplete response to radioiodine has been confirmed with the ROC curve analysis and the best proposed cut-off value was 8.17 ng/mL (sensitivity 55%, specificity 77%, positive predictive value 42.1%, negative predictive value 84.7%); sTg over 8.17 ng/mL increases the risk of incomplete response to therapy 2.5-folds (P=0.002). CONCLUSIONS: sTg, assessed at the moment of qualification to radioiodine therapy, as the most important factor determining incomplete response to radioiodine therapy in patients with DTC, should be particularly taken into consideration in predicting the future course of the disease as well as treatment and follow-up planning. Radical thyroidectomy may help to increase the effectiveness of treatment.

Does nesfatin-1 influence the hypothalamic-pituitary-gonadal axis in adult males with obstructive sleep apnoea?

There is growing evidence that obstructive sleep apnoea (OSA) influences the hypothalamic-pituitary-gonadal axis (HPG axis) in men. The aim of the study was to assess the association of nesfatin-1 with HPG axis disturbances in OSA. This is a prospective study with consecutive enrolment. It comprises 72 newly diagnosed OSA patients ((AHI: apnoea-hypopnea index) 18 subjects: 5 ≤ AHI < 15; 24: 15 ≤ AHI < 30; 30: AHI ≥ 30) and a control group composed of 19 patients (AHI < 5). All patients underwent polysomnography and fasting blood collection for nesfatin-1, testosterone, luteinising hormone (LH), high-sensitivity C-reactive protein (hsCRP), aspartate transaminase (AST), alanine aminotransferase (ALT), creatinine and glucose. Groups had similar levels of LH, nesfatin-1 and testosterone (p = 0.87; p = 0.24; p = 0.08). Nesfatin-1 was not correlated to LH (p = 0.71), testosterone (p = 0.38), AHI (p = 0.34) or the oxygen desaturation index (ODI) (p = 0.69) either in the whole group, or in sub-groups. The study did not reveal any association between the HPG axis and nesfatin-1 in OSA adult males. It is possible that nesfatin-1 is not a mediator of HPG axis disturbances in adult patients with OSA.

Klotho expression and nodal involvement as predictive factors for large cell lung carcinoma.

INTRODUCTION: Klotho has been recently described as a carcinogenesis suppressor. Large cell neuroendocrine lung carcinoma (LCNEC) is a rare, highly malignant neoplasm. In the light of increasing incidence of neuroendocrine tumours, biomarkers predicting survival are needed. We consider that Klotho might be one. MATERIAL AND METHODS: We analysed records of all patients diagnosed with LCNEC, atypical carcinoid and typical carcinoid operated on in our institution between 2007 and 2015. Initially, we found 134 cases. Forty-six specimens were unattainable and thus excluded from research. All patients diagnosed with LCNEC according to the WHO classification were included in the study. Immunohistochemical staining for Klotho was performed. We retrospectively reviewed patient charts and analysed multiple variables. RESULTS: Positive staining for Klotho was present in 36 tissue specimens, while 12 patients were Klotho-negative. Survival length was significantly higher in Klotho-positive cases (p = 0.024), while advanced nodal status (N1 and N2) represented a marker of poor outcome (p = 0.011). In multivariate analysis, both Klotho presence (p = 0.015; HR = 0.37; 95% CI: 0.17-0.86) and nodal involvement (p = 0.007; HR = 3.04; 95% CI: 1.37-6.82) were independent prognostic factors. Tumour vessel invasion and visceral pleura infiltration were not associated with worse treatment results. Klotho presence predicted a favourable prognosis in these groups (p = 0.018; p = 0.007). CONCLUSIONS: Our results suggest that Klotho might be a positive factor for predicting survival in LCNEC and nodal involvement a negative one. Thus, these two markers may assist in the selection of subjects with unfavourable prognosis and to personalise therapy regimens.

Changes in total and acylated ghrelin levels during mitotane treatment in patients with adrenocortical carcinoma.

INTRODUCTION: Adrenocortical carcinoma (ACC) is a highly aggressive cancer with poor prognosis. Mitotane is the only approved drug for ACC treatment. Tolerability and efficacy of mitotane is variable. There is evidence that ghrelin may affect cancer development and the occurrence of side effects. OBJECTIVES: We examined the differences in plasma ghrelin concentrations between patients with benign adrenal tumors and adrenal carcinoma. We also investigated the effect of mitotane treatment on circulating plasma ghrelin levels in patients with ACC. Additionally, we assessed the relationship between ghrelin concentrations, mitotane levels, and side effects of mitotane treatment. PATIENTS AND METHODS: We enrolled 26 patients with ACC and 42 controls with adrenocortical adenoma (ACA). Clinical and histopathologic features, hormonal secretion pattern, and plasma acylated and total ghrelin levels were measured in every patient. Serum mitotane levels, body mass index, and side effects of mitotane treatment were estimated every 3 to 12 weeks during follow­up in patients with ACC. RESULTS: There was no significant difference in total and acylated ghrelin concentrations between ACC and ACA groups before mitotane introduction in ACC. We observed that during mitotane treatment, both total and acylated ghrelin levels became elevated in ACC compared with ACA. A positive correlation was found between circulating mitotane levels and acylated ghrelin as well as the ratio of acylated to total ghrelin levels in all patients treated with mitotane. Higher ghrelin levels were associated with increased risk of side effects. CONCLUSIONS: Plasma ghrelin levels are changed during mitotane treatment. These changes may be connected with side effects of mitotane.

Association of total, acylated and unacylated ghrelin with apolipoprotein A1 and insulin concentrations in acromegalic patients.

BACKGROUND: Ghrelin is a hormone that occurs in acylated (AG) or unacylated (UG) form. Ghrelin strongly stimulates growth hormone (GH) secretion from anterior pituitary, as well as regulates the energy balance and various metabolic parameters. Increased consideration is given to UG, thought to be inactive. OBJECTIVES: We aimed to evaluate the levels of total ghrelin, AG and UG in medically naive and treated patients with biochemically active acromegaly, with respect to variables of lipid and glucose metabolism. MATERIAL AND METHODS: We studied total ghrelin, AG and calculated UG levels in a group of 24 patients with active acromegaly and 15 healthy controls. Plasma levels of GH, insulin-like growth factor 1 (IGF-1), insulin, glucose, total cholesterol (TC), high-density lipoprotein (HDL) cholesterol and calculated low-density lipoprotein (LDL) cholesterol, triglycerides (TG), apolipoproteins A1 (APO A1), and B-100 (APO B-100) were measured. RESULTS: Patients with acromegaly revealed lower levels of total ghrelin than healthy controls. In pooled data of all subgroups, simple linear regression analysis revealed that total ghrelin concentration was significantly associated with APO A1 concentration (ß = 0.8087; p = 0.0315) and AG concentration was significantly associated with fasting insulin concentration (ß = 15.5183; p = 0.011). There was an inverse association between UG and the patients' age, and positive association between UG and APO A1. CONCLUSIONS: Our results suggest that ghrelin may influence metabolic disturbances in acromegaly. It seems that the assessment of AG and UG is superior to total ghrelin measurement. Mechanisms regulating ghrelin acylation and function of each form need elucidation in order to improve diagnostics and treatment of metabolic disturbances, not only acromegaly.

18F-FDG PET/CT and nestin expression as prognostic tools in pulmonary neuroendocrine tumours.

OBJECTIVES: The aim of this study was to investigate the fluorine-18-fluorodeoxyglucose (F-FDG) uptake on integrated PET [PET/computed tomography (CT)] images and its correlation with nestin expression in a series of neuroendocrine lung tumours. As the incidence of neuroendocrine lung tumours is rising, tools predicting diagnosis, outcome and assisting in the selection of treatment regimens are needed. PATIENTS AND METHODS: We reviewed records of patients diagnosed with large cell neuroendocrine lung carcinoma, atypical carcinoid and typical carcinoid who were operated upon in our institution. Into the study, we included those who underwent F-FDG PET/CT before the operation. Immunohistochemical staining for nestin was performed. We retrospectively reviewed patient charts and analyzed multiple variables. RESULTS: Maximal standardized uptake value (SUVmax) was significantly higher in poorly differentiated than in well-differentiated tumours (P<0.001). The estimated SUVmax cut-off value, which distinguishes large cell neuroendocrine lung carcinoma from carcinoid with the highest sensitivity and specificity (88.6%; 85%), was 6.3. Positivity of the tumour on F-FDG PET/CT was associated with shorter survival of the patient (P=0.0057). Multivariate analysis showed that nodal involvement and SUVmax were predictors of adverse outcome. Nestin expression did not correlate with lymph node metastases (P=0.97), SUVmax (P=0.9), maximal size of the lesion (P=0.49) or Ki-67 (P=0.93). Nestin expression did not influence survival on multivariate analysis. CONCLUSION: The study revealed a comparable expression of nestin in tumours with different activity of glucose metabolism measured by F-FDG uptake at PET/CT. It did not show any significant influence of nestin expression on survival. The study confirmed that F-FDG PET/CT is useful in the preoperative evaluation of patients with pulmonary neuroendocrine tumours.

Airway Obstruction in Sleep Apnea Patients.

Obstructive sleep apnea (OSA) is a condition of breathing pathology occurring during sleep, characterized by repeated episodes of upper airway obstruction. The aim of the study was to determine the occurrence of airway obstruction in smoking males with OSA in whom lung function tests had not been performed before. One hundred and four current smokers selected from 1241 patients were enrolled for the research. The subjects included in the study smoked minimum 20 cigarettes a day for at least 10 years. The diagnosis of OSA was confirmed by polysomnography (PSG) in the Sleep Laboratory and subjects were assigned to one of three groups, depending on the severity of OSA. The control group consisted of 30 age-matched male smokers in whom OSA was not confirmed in PSG. Patients from the study and control group scored ≥ 11points in the Epworth Sleepiness Scale. Spirometry, impulse oscillometry, and body plethysmography were used to assess pulmonary function. Airflow limitation in subjects of the control group and OSA patients was confirmed. There were no significant differences in the incidence of bronchial obstruction between the control and study groups, and among the patients of various OSA severity. We conclude that the severity of OSA in smokers does not associate with the presence of airway obstruction. However, the increased peripheral respiratory resistance found in oscillometry did relate to a longer smoking time in OSA patients.

Association between bone remodeling and inflammatory markers in obstructive sleep apnea in relation to disease severity.

INTRODUCTION    There is growing evidence that obstructive sleep apnea (OSA) influences both bone metabolism and structure. Chitinase­3­like protein 1 (YKL­40) is a novel inflammatory and remodeling marker, the levels of which were shown to increase in OSA. YKL­40 can probably alter the bone turnover. OBJECTIVES    The aim of the study was to assess a possible interplay between YKL­40 and bone turnover markers in patients with different stages of OSA, and to evaluate the relation between bone mass, severity of OSA, and YKL­40 levels. PATIENTS AND METHODS    The study involved 72 male patients with OSA. They were divided into 3 groups according to disease severity, using the apnea-hypopnea index (AHI): group 1 (n = 18; 5≤ AHI <15), group 2 (n = 25; 15≤ AHI <30), and group 3 (n = 29; AHI ≥30). All patients underwent polysomnography and densitometry. Fasting blood samples were collected for YKL­40, C­terminal telopeptide of typeI collagen (CTX), procollagen type 1 N­terminal propeptide (P1NP), and other markers. RESULTS    P1NP differed between groups 1 and 2, as well as groups 1 and 3 (P = 0.02). Group 2 had higher CTX levels than group 1 (borderline significance, P = 0.05). A simple linear regression analysis showed that serum YKL­40 levels were associated with the levels of CTX (P <0.0001, ß = 0.9871) and P1NP (P <0.0001, ß = 0.9780). CONCLUSIONS    Our study might suggest that YKL­40 is associated with bone turnover in OSA. We may assume that this marker influences both bone formation and destruction; thus, OSA could be characterized by preserved bone mineral density.

Anti-thyroidal peroxidase antibodies are associated with thyrotropin levels in hypothyroid patients and in euthyroid individuals.

OBJECTIVE: The study was designed to evaluate the relationship between thyroid antibodies and gland dysfunction, with the aim of finding a clinically useful threshold value of thyreoperoxidase antibodies, which could prove to be predictive for thyroid failure. MATERIAL AND METHODS: The study was conducted on 99 women, ages ranging from 18-91 years (mean age: 45.5 ±17.0), were treated as outpatients in the Department of Endocrinology, Metabolism and Internal Medicine. Analysis of serum samples for TSH concentration and anti-TPO titers was conducted. RESULTS: The most common disorder was hypothyroidism. Anti-TPO titers above reference range values were observed in 35 patients (35.4%): 21 (60%) were hypothyroid and 11 (31.4 %) were euthyroid. The anti-TPO and TSH serum levels correlated both in patients with high thyroid antibody titers, and in the anti-TPO negative groups. To find the threshold value of anti- TPO that would help predict hypothyroidism, receiver operating curves were used. With this approach, TPO antibody titers over 17 IU/ml indicated hypothyroidism with a 90% sensitivity and 75% sensibility. CONCLUSIONS: It can be postulated that the cutoff values of anti-TPO in the general population should be decreased in order to improve autoimmune thyroid disorder screening. Obviously, using that margin may lead initially to the detection of some false positive subjects. However, with lower cut-off values, more patients can be enrolled into thyroid follow-up groups. In this way, many people could avoid complications of undiagnosed, insidious thyroid failure.

Obstructive sleep apnea and hormones - a novel insight.

Obstructive sleep apnea (OSA), a disorder characterized by repetitive collapse of the upper respiratory tract during sleep, occurs in about 4% of middle-aged men and 2% of women. The incidence of the disorder is rising due to an increase in obesity and ageing of the population. Patients with obstructive sleep apnea are at elevated risk of some endocrinal and metabolic disorders, which may lead to serious consequences including shortening of life expectancy. The recognition and understanding of interactions between local upper airway dysfunction and its endocrinal consequences is therefore vital. In this review we will focus on the influence of OSA on bone metabolism and endocrine homeostasis.