Cancer stem cells (CSCs), known also as tumor-initiating cells, are quiescent, pluripotent, self-renewing neoplastic cells that were first identified in hematologic tumors and soon after in solid malignancies. CSCs have attracted remarkable research interest due to their role in tumor resistance to chemotherapy and radiation treatment as well as recurrence. Extensive research has been devoted to the role of CSCs in glioblastoma multiforme (GBM), the most common primary brain tumor in adults, which is characterized by a dismal prognosis because of its aggressive course and poor response to treatment. The aim of the current paper is to provide an overview of current knowledge on the role of cancer stem cells in the pathogenesis and treatment resistance of glioblastoma. The six regulatory mechanisms of glioma stem cells (GSCs)—tumor microenvironment, niche concept, metabolism, immunity, genetics, and epigenetics—are reviewed. The molecular markers used to identify GSCs are described. The role of GSCs in the treatment resistance of glioblastoma is reviewed, along with future treatment options targeting GSCs. Stem cells of glioblastoma thus represent both a driving mechanism of major treatment difficulties and a possible target for more effective future approaches.

In this study we assessed whether gliomas could be subdivided into different molecular subtypes by immunohistochemistry (IHC) reminiscent of those first described by Verhaak et al. in 2010 (classical, proneural, mesenchymal and neural). We also evaluated the prognostic significance of single...

Thyroid nodules are frequent in general population, found in 3.7–7% of people by palpation and 42–67% by ultrasonography (US). The differential diagnosis ranges from papillary (PC), follicular (FC) and medullary (MC) carcinomas to follicular adenoma (FA) and colloid goitre. Cancer risk in thyroid nodules varies: 5% in masses found by palpation, 1.6–15% by US, 3.9–11.3% by computed tomography (CT), 5–6% by magnetic resonance imaging (MRI) and 30–50% by positron emission tomography (PET). The final diagnosis depends on fine needle aspiration (FNA) findings and histopathology. The recent WHO classification (2017) is based on classic morphology, including assessment of invasion and nuclei. New entities are defined to designate tumours with doubtful invasion or controversial nuclear features. By immunohistochemistry, PC expresses HBME-1, TROP-2, CITED1 and CK19. Notably, PC can stain for CD20. MC is recognised by neuroendocrine differentiation. To distinguish FA vs. FC, evaluation of HBME-1, p27 and galectin has been suggested. Regarding miRNAs, miR-146b, miR-222, miR-221 and miR-181b are upregulated, while miR-145, miR-451, miR-613 and miR-137 are downregulated in PC. FC features downregulated miR-199a-5p and upregulated miR-197 and miR-346. In MC, miR-21 and miR-129-5p are downregulated. In addition, increased systemic inflammatory reaction can be poor prognostic factor in thyroid cancer. The aim of this chapter is to review classic and innovative histopathology of thyroid nodules for diagnostic pathology practice and research in multidisciplinary thyroid teams.

Summary Introduction. Meningiomas are common primary tumors of brain meninges. These neoplasms develop from arachnoid cap cells and are multiple in 1 - 10% cases. Occasionally, significantly higher multiplicity rates have been reported, at least partially due to the increased application of computed tomography and magnetic resonance imaging in the diagnostics of intracranial pathologies. Meningiomas generally express progesterone receptors, but only few studies have focused on sex hormone receptor differences between solitary and multiple meningiomas. Similarly, there is limited information on cell proliferation and adhesion factors in solitary and multiple meningiomas. Aim of the study. Was to evaluate the immunohistochemical differences in sex hormone receptor expression, cell proliferation and adhesion within solitary and multiple meningiomas. Material and methods. In a retrospective study, 11 consecutive multiple meningiomas and 20 grade-matched solitary meningiomas were assessed by immunohistochemistry (IHC) to detect estrogen receptors (ER), progesterone receptors (PR), Ki-67 and neural cell adhesion molecule (NCAM). IHC was followed by quantitative microscopic evaluation. Descriptive and inferential statistics was applied including confidence interval (CI) analysis, Mann-Whitney U test and Spearmen correlation by IBM SPSS Statistics 22.0 software; p values less than 0.05 were regarded as statistically significant. Results. Although PR were found in all samples, the mean expression was significantly lower in multiple meningiomas (p = 0.03): 30.0% (95% CI: 10.4 - 49.8) versus 70.6% (95% CI: 56.6 - 84.7) in solitary meningiomas. ER were invariably absent in both groups. The proliferation index did not differ in solitary and multiple tumors. There was a trend (p = 0.07) to higher mean expression of NCAM in multiple meningiomas than in control group: 48.3% (95% CI: 25.8 - 70.8) versus 24.6% (95% CI: 13.2 - 36.0), respectively. The multiple meningiomas showed diverse histological types and immunophenotypes in up to 33.3% patients. Conclusions. Multiple meningiomas are characterized by significant down-regulation of PR and up-regulation of NCAM. The last finding can indicate neural differentiation and/ or peculiarities of cell adhesion and signaling that facilitate multifocal proliferation. Diverse histological types as well as PR and NCAM expression in separate meningiomas within same patient indicate independent multicentric origin.

Glioblastoma (GBM) ir viens no biežākajiem un agresīvākajiem centrālās nervus sistēmas (CNS) audzējiem, kas ir augstākās anaplāzijas pakāpes glioma (4. anaplāzijas pakāpe). Neskatoties uz standartterapiju, kas iekļauj maksimāli iespējamu audzēja rezekciju, kuru papildina ar adjuvantu ķīmijterapiju ar temozolamīdu un radioterapiju, prognoze pacientiem ar GBM ir ļoti slikta. Jaunu potenciālu molekulāru un imūnhistoķīmisku marķieru atklāšanu un pētīšana varētu palīdzēt uzlabot mūsu zināšanas par kādām kritiskām molekulārām izmaiņām, kas veicina audzēja attīstību un šādas zināšanas palielina iespēju izveidot efektīvu uz mērķa molekulu vērstu terapiju nākotnē. Jauni molekulāri un imūnhistoķīmiski prognostiski marķieri var uzlabot ārstēšanu un iespējams arī ļaut sadalīt pacientus vairākās prognostiskās grupās ar atšķirīgu ārstēšanas pieeju, kas padarītu terapiju vairāk personalizētu. Šī pētījuma mērķis ir izvērtēt gliomu- GBM un difūzu astrocitomu (DA), morfoloģisko un imūnhistoķīmisko profilu, kā arī izvērtēt atsevišķus imūnhistoķīmiskus marķierus un iespēju vienkāršoti veikt gliomu subtipēšanu, izmantojot imūnhistoķīmijas (IHĶ) metodi. Pētījums ir retrospektīvs, kurā tika analizēti formalīnā fiksēti parafīnā ieguldīti ķirurģiski rezecētu gliomu audi. Pētījumā veikta plaša morfoloģiska un imūnhistoķīmiska izvērtēšana, kur kopumā tikai vērtēti 8 imūnhistoķīmiskie parametri, iekļaujot izdzīvotības analīzi. Datu statistiskai apstrādei tika izmantota aprakstošā un analītiskā metode. Pētījumā tika iekļauti 172 gliomu pacienti, no tiem 146 GBM un 26 DA pacienti. Pētījumā tika konstatēts, ka GBM pacientiem ir slikta prognoze ar mediāno izdzīvotību 7,9 mēneši, kas ir nedaudz zem dzīvildzes rādītājiem citās valstīs. No pētījumā izmantotajiem marķieriem, tikai izocitrātdehidrogenāzes 1 (IDH1) R132H mutācijas klātbūtne ir visnozīmīgākais prognostiskais faktors gliomām. Pacientiem ar DA, augsta trombocītu atbrīvotā augšanas faktora receptora alfa (PDGFRA) ekspresija arī ir saistīta ar labākiem izdzīvotības rādītājiem. Tika konstatēts, ka daži imūnhistoķīmiskie marķieri, tādi kā CD44, p21, PDGFRA un Ki-67 proliferācijas indekss ir parametri, kas atkarīgi no gliomu anaplāzijas pakāpes, tādējādi augstas anaplāzijas pakāpes gliomas, kā GBM, novēroja augstu CD44, Ki-67 un p21 ekspresiju. Savukārt, p27 un PDGFRA ir daudz zemāka GBM, salīdzinot ar DA. Interesanti, bet dažu marķieru ekspresijai (p27, CD44, Ki-67) bija arī dzimumatšķirības. GBMs, šūnas cikla proteīni, tādi kā p53, p21 un p27 ir arī iesaistīti dažādos mehānismos, kas regulē angioģenēzi un šūnu proliferāciju. Cieša saistība ir atklāta starp PDGFRA un p53 ekspresiju gliomās. DA gadījumos, PDGFRA novēroja negatīvu korelāciju ar CD44 un p21 kā arī mikroasinsvadu blīvumu (MVB). Pētījuma noslēgumā pierādīts, ka gliomu subtipēšana ir iespējama ar IHĶ metodi, izmantojot nelielu marķieru skaitu- PDGFRA, p53, IDH1 R132H un CD44. Ir konstatēts arī tas, ka augsta CD44 ekspresija ir nozīmīgs GBM mezenhimāla subtipa rādītājs, kas ir saistīts ar sliktāku atbildi uz radioterapiju.

Glioblastoma (GBM) is one of the most common and aggressive tumours of the central nervous system (CNS) and represents the highest grade (grade IV) of glioma. Despite the standard therapy with maximal possible resection, followed by radiotherapy and chemotherapy with temozolomide, the prognosis for GBM patients remains dismal. Identification and research of potential molecular and immunohistochemical markers will help to increase our awareness of critical molecular changes in tumorigenesis and increase the possibility of effective molecularly targeted therapy in future. New molecular and immunohistochemical prognostic markers can improve the treatment and even allow patients to be stratified into different prognostic groups, which will make the therapy more personalized. The aim of this research was to evaluate the morphological and immunohistochemical profile of gliomas ‒ glioblastoma (GBM) and diffuse astrocytoma (DA) ‒ as well as to evaluate the prognostic role of single immunohistochemical markers and the possibility of glioma subtyping by immunohistochemistry (IHC). This work was performed as a retrospective study that is based on the analysis of formalin-fixed, paraffin-embedded, surgically treated human glioma tissues. In the study, a comprehensive morphological and immunohistochemical evaluation was performed including analysis of eight immunohistochemical parameters and survival analysis by applying a wide range of descriptive and analytic statistic methods. A total of 172 patients with gliomas were enrolled in the research work, including 146 GBMs and 26 DAs. It was found that GBM patients were characterized by poor prognosis with a median survival time of 7.9 months, which is slightly below the survival rates reported in other countries. From the selected markers, the presence of isocitrate dehydrogenase 1 (IDH1) R132H mutation was the most significant prognostic factor of better survival in gliomas. However, in patients with DAs, high platelet-derived growth factor receptor alpha (PDGFRA) expression was also associated with significantly better survival. Some immunohistochemical markers, such as CD44, p21, p27, PDGFRA and Ki-67 proliferation, are grade-specific parameters in gliomas, thus CD44, Ki-67 and p21 are significantly upregulated; however, p27 and PDGFRA are downregulated in high-grade gliomas such as GBM. Surprisingly, gender-related differences were found in the expression of some immunohistochemical markers, such as p27, CD44 and Ki-67, in gliomas. In GBMs, cell cycle proteins, such as p53, p21 and p27, are involved in a variety of mechanisms that regulate proliferation and angiogenesis. A strong relationship was also found between the expression of PDGFRA and p53 in gliomas. In DAs, PDGFRA correlated inversely with CD44, p21 and microvascular density (MVD). Finally, it was found that subtyping of gliomas is possible by IHC using a limited number of markers – PDGFRA, p53, IDH1, R132H and CD44. In addition, the expression of CD44 was shown to be a reliable indicator of mesenchymal subtype in GBM, which has a worse response to radiotherapy.