Short histological kaleidoscope - recent findings in histology. Part III.

The paper provides an overview of the current understanding of different cells' biology (e.g., keratinocytes, Paneth cells, myoepithelial cells, myofibroblasts, chondroclasts, monocytes, atrial cardiomyocytes), including their origin, structure, function, and role in disease pathogenesis, and of the latest findings in the medical literature concerning the brown adipose tissue and the juxtaoral organ of Chievitz.

Short histological kaleidoscope - recent findings in histology. Part II.

This article focuses on the latest histological knowledge in the field regarding the peripheral lymphoid system [mucosa-associated lymphoid tissue (MALT), bronchus-associated lymphoid tissue (BALT), gut-associated lymphoid tissue (GALT)], the thymus stroma, some of the various corpuscles of the human body (Hassall's corpuscles in thymus, arenaceous corpuscles in pineal gland, corpora amylacea in prostate and other locations) and Fañanas glial cells in the cerebellum.

Short histological kaleidoscope - recent findings in histology. Part I.

This article is a review of new advances in histology, concerning either classification or structure of different tissular elements (basement membrane, hemidesmosomes, urothelium, glandular epithelia, adipose tissue, astrocytes), and various organs' constituents (blood-brain barrier, human dental cementum, tubarial salivary glands, hepatic stellate cells, pineal gland, fibroblasts of renal interstitium, Leydig testicular cells, ovarian hilar cells), as well as novel biotechnological techniques (tissue engineering in angiogenesis), recently introduced.

Assessment of mismatch repair deficiency, CDX2, beta-catenin and E-cadherin expression in colon cancer: molecular characteristics and impact on prognosis and survival - an immunohistochemical study.

Microsatellite instability (MSI) or the deficiency of mismatch repair (MMR) proteins is one of the molecular pathways of colorectal tumorigenesis and may have important clinical implications in predicting the treatment response. We evaluated the relationship between clinicopathological features and MMR proteins [mutL homologue 1 (MLH1), mutS homologue 2 (MSH2), mutS homologue 6 (MSH6), postmeiotic segregation increased 2 (PMS2)], adhesion molecules (E-cadherin, beta-catenin) and caudal-type homeobox 2 (CDX2) in 31 patients with colon adenocarcinoma, using immunohistochemistry. We also aimed to assess the prognostic value of the studied proteins. MLH1 loss was correlated to PMS2 loss (p=0.006) and MSH2 loss (p=0.023); MSH2 loss was significantly associated to MSH6 loss (p=0.011). Tumors with MSH6 loss, together with tumors with PMS2 loss, covered all the patients with MSI status. We found a significant correlation between MSI tumors and mucinous histological type (p=0.03), but no significant associations with other clinicopathological features or with survival rate. There was a significant correlation between E-cadherin expression and differentiation degree (p=0.018) and between beta-catenin expression and lymph node invasion (p=0.046). No significant association between CDX2 loss and any clinical or pathological features was found (p>0.05). No significant differences were identified in overall survival according to E-cadherin, beta-catenin or CDX2 expression (p>0.05). In our study, PMS2 loss was significantly correlated with CDX2 loss (p=0.03). In conclusion, the molecular analysis of biological markers for colon cancer may be important for patient stratification, in order to select the optimal treatment algorithm. Our results suggest that probably the double panel (MSH6 and PMS2) is enough to detect the MSI status, instead of using the quadruple panel.

Vascular endothelial growth factor (VEGF) - key factor in normal and pathological angiogenesis.

Vascular endothelial growth factor (VEGF) represents a growth factor with important pro-angiogenic activity, having a mitogenic and an anti-apoptotic effect on endothelial cells, increasing the vascular permeability, promoting cell migration, etc. Due to these effects, it actively contributes in regulating the normal and pathological angiogenic processes. In humans, the VEGF family is composed of several members: VEGF-A (which has different isoforms), VEGF-B, VEGF-C, VEGF-D, VEGF-E (viral VEGF), VEGF-F (snake venom VEGF), placenta growth factor (PlGF), and, recently, to this family has been added endocrine gland-derived vascular endothelial growth factor (EG-VEGF). VEGF binds to tyrosine kinase cell receptors (VEGFRs): VEGFR-1 [Fms-like tyrosine kinase 1 (Flt-1)], VEGFR-2 [kinase insert domain receptor (KDR) in human; fetal liver kinase 1 (Flk-1) in mouse] and VEGFR-3 [Fms-like tyrosine kinase 4 (Flt-4)]. While VEGFR-1 and VEGFR-2 are expressed predominantly on vascular endothelial cells, VEGFR-3 is expressed especially on lymphatic endothelial cells. VEGFR-2 has the strongest pro-angiogenic activity and a higher tyrosine kinase activity than VEGFR-1. Endothelial cells also express co-receptors, such as neuropilin-1 (NP-1) and neuropilin-2 (NP-2), which modulate tyrosine kinase receptor activity. Both VEGF and VEGFRs are expressed not only on endothelial cells, but also on non-endothelial cells. This article aims to highlight the most recent data referring to the VEGF family and its receptors, as well as its implications in the angiogenesis process. At present, blocking angiogenesis in cancer or in other pathological processes, using anti-VEGF and anti-VEGFRs therapies, is considered to be extremely important.

Molecular markers in the diagnosis of invasive pituitary adenomas - an immunohistochemistry study.

Pituitary adenomas are benign tumors of the brain, with a relatively high prevalence in the general population, being responsible for 14.4-16.7% from all brain tumors. These tumors, although benign, have a local invasive behavior in approximately 35% of the cases. The aim of this study was to identify the differences in expression of molecular markers between primary and relapsed pituitary adenomas (as an aggressiveness indicator), as well between secreting and non-secreting pituitary adenomas. Tumor fragments were collected from 51 patients with invasive pituitary adenomas. Of these, 10 cases were operated a second time due to tumor recurrence. The tumor fragments were retrieved from the archives of the Department of Pathology, Emergency County Hospital, Cluj-Napoca, Romania. Immunohistochemical staining was performed for nine markers on 51 invasive pituitary adenomas: Ki-67, ß-catenin, E-cadherin, Bcl-2, galectin-3, p53, p27, CD117, and CD44. We compared the expression differences between two groups: the first one including primary and relapsed invasive pituitary adenomas, and another one including prolactin (PRL)-secreting and non-secreting invasive pituitary adenomas. Ki-67, p53 and Bcl-2 expressions were found significant in the PRL-secreting group. CD44 immunostaining was significant only in relapsed invasive pituitary adenomas. For the ß-catenin, E-cadherin, galectin-3, p27 and CD117 expression levels were not registered statistically significant differences between our groups. Our study is the first one to report a statistically significant difference between the expression of CD44 in primary and relapsed invasive pituitary adenomas and it could be used as a negative impact prognostic marker.