Miljan Krstić

Gastric cancer stem cells: therapeutic targets

During the past decade, a growing body of evidence has implied that cancer stem cells (CSCs) play an important role in the development of gastric cancer (GC). The notion that CSCs give rise to GC and may be responsible for invasion, metastasis, and resistance to treatment has profound implications for anti-cancer therapy. Recent major advances in the rapidly evolving field of CSCs have opened novel exciting opportunities for developing CSC-targeted therapies. Discovery of specific markers and signaling pathways in gastric CSCs (GCSCs), with the perfecting of technologies for identification, isolation, and validation of CSCs, may provide the basis for a revolutionary cancer treatment approach based on the eradication of GCSCs. Emerging therapeutic tools based on specific properties and functions of CSCs, including activation of self-renewal signaling pathways, differences in gene expression profiles, and increased activity of telomerase or chemoresistance mechanisms, are developing in parallel with advances in nanotechnology and bioengineering. The addition of GCSC-targeted therapies to current oncological protocols and their complementary application may be the key to successfully fighting GC.

Development of c-kit immunopositive interstitial cells of Cajal in the human stomach.

Interstitial cells of Cajal (ICC) include several types of specialized cells within the musculature of the gastrointestinal tract (GIT). Some types of ICC act as pacemakers in the GIT musculature, whereas others are implicated in the modulation of enteric neurotransmission. Kit immunohistochemistry reliably identifies the location of these cells and provides information on changes in ICC distribution and density. Human stomach specimens were obtained from 7 embryos and 28 foetuses without gastrointestinal disorders. The specimens were 7–27 weeks of gestational age, and both sexes are represented in the sample. The specimens were exposed to anti‐c‐kit antibodies to investigate ICC differentiation. Enteric plexuses were immunohistochemically examined by using anti‐neuron specific enolase and the differentiation of smooth muscle cells (SMC) was studied with anti‐α smooth muscle actin and anti‐desmin antibodies. By week 7, c‐kit‐immunopositive precursors formed a layer in the outer stomach wall around myenteric plexus elements. Between 9 and 11 weeks some of these precursors differentiated into ICC. ICC at the myenteric plexus level differentiated first, followed by those within the muscle layer: between SMC, at the circular and longitudinal layers, and within connective tissue septa enveloping muscle bundles. In the fourth month, all subtypes of c‐kit‐immunoreactivity ICC which are necessary for the generation of slow waves and their transfer to SMC have been developed. These results may help elucidate the origin of ICC and the aetiology and pathogenesis of stomach motility disorders in neonates and young children that are associated with absence or decreased number of these cells.

Epithelial ovarian cancer with CD117 phenotype is highly aggressive and resistant to chemotherapy

CD117 expression has a pathogenic role in many malignancies, including ovarian carcinoma. The aim of the present study was to examine the correlation of stemness‐associated marker CD117 with the clinicopathologic features of epithelial ovarian cancer and patient survival.

An approach to malignant mammary phyllodes tumors detection.

BACKGROUND/AIM Mammary phyllodes tumors (MPT) are uncommon fibroepithelial (biphasic) neoplasms whose clinical behavior is difficult to predict on the basis of histological criteria only. They are divided into benign, borderline malignant and malignant groups. Sometimes it appears difficult to distinguish these tumors from other types of soft tissue sarcomas. Because of the relatively scant data on the role of biological markers in MPT histogenesis, we have decided to undertake the following study, trying to shed more light on the issue by investigating the following elements that make up MPT: their histological patterns, biological behavior, enzymohistochemical, histochemical and immunohistochemical characteristics (ICH) together with the mast cell analysis. METHODS We examined the biopsy material of 35 MPT in our laboratory. Enzymohistochemistry was performed on frozen sections (method of Crowford, Nachlas and Seligman). The used methods were classical hematoxylin-eosin (H & E); histochemical Massontrichrome, Alcian-blue, Periodic acid Schiff and immunohistochemical LSAB2 method (DacoCytomation). Ki-67, c-kit, vimentin, estrogen receptor (ER), progesterone receptor (PR) and Her-2 oncoprotein immunohistochemistry was performed on all tumors. RESULTS The patients were ranged per age from 30--62 years (mean 43.3 years, median 39 years). A total of 35 cases of MPT were included: 20 benign (57%), 6 borderline malignant (17%) and 9 malignant (26%). Twenty-two patients (62.8%) underwent segmental mastectomy, while 13 (37.2%) had total mastectomies. Twenty-eight patients had negative surgical margins at original resection. The mean size of malignant MPT (7.8 cm) was larger than that of benign MPT (4.5 cm). Significant features of the malignant MPT were: stromal cellularity, stromal cellular atypism, high mitotic activity, atypic mitoses, stromal overgrowth, infiltrative tumor contour and heterologous stromal elements. Benign MPT showed strong enzymohistochemical Leucine Amino Peptidase (LAP) activity in both epithelial and stromal components while it was weak or absent in the epithelial parts of the malignant tumors. Acid mucopolysacharides were present in the stromal component of all types of these tumors. Benign MPT had a lower Ki-67 than did borderline malignant MPT (4 versus 28). Malignant MPT had a greater than 8-fold higher Ki-67 activity than did benign tumors (35 versus 4). Intracyto-plasmatic c-kit expression was associated with a pathological diagnosis of malignant MPT, correlating with increasing grade (p < 0.05). In hypercellular stroma of borderline malignant and especially malignant forms of MPT, high activity of ER in mast cells was confirmed. Oncoprotein Her-2 activity, mostly in epithelial components, correlated with the degree of malignant progression of MPT (p < 0.05). CONCLUSION Besides the well-known malignant features additional parameters have been found to be high Ki-67 and c-kit stromal expressions, and weak LAP activity in the epithelial part of malignant MPT, as well as mast cells with a high expression of ER.

Morphometric analysis of the human anterior pituitary's folliculostellate cells during the aging process

Folliculostellate cells represent non-endocrine cells of the anterior pituitary which influence the function of the endocrine cells via paracrine action. Though there is a lack of literature data on their presence during human aging, the aim of this research was to perform the quantification of anterior pituitary folliculostellate cells by the application of immunohistochemical and morphometric methods. The material for the study consisted of 15 anterior pituitaries taken from cadavers at routine autopsy. Their tissue was processed by standard histological procedure and the obtained histological slices were stained by S100 polyclonal antibody. Digital images of stained histological sections were analyzed by morphometric method with ImageJ system. The volume density of S100 positive cells was measured for each case. Results of morphometric and statistical analysis showed a significantly positive correlation between folliculostellate cell volume density and the age of the evaluated cases. Linear regression additionally showed that the age significantly predicts folliculostellate cells volume density in our sample. Further, all cases were classified into three age groups and One Way ANOVA showed that the volume density of folliculostellate cells was significantly higher only in the third age group in relation to the first and the second group, respectively. Volume densities of the first and the second age groups were not significantly different. So, the results of our study pointed to the conclusion that folliculostellate cells presence generally increases with age, but this increase is significant only in the oldest cases and might represent the modality of successful anterior pituitary aging.

Morphometric analysis of the folliculostellate cells and luteinizing hormone gonadotropic cells of the anterior pituitary of the men during the aging process

The aim of this research was to quantify the changes in the morphology and density of the anterior pituitary folliculostellate (FS) and luteinizing hormone (LH) cells. Material was tissue of the pituitary gland of the 14 male cadavers. Tissue slices were immunohistochemically stained with monoclonal anti-LH antibody and polyclonal anti-S100 antibody for the detection of LH and FS cells, respectively. Digital images of the stained slices were afterwards morphometrically analyzed by ImageJ. Results of the morphometric analysis showed significant increase of the FS cells volume density in cases older than 70 years. Volume density of the LH cells did not significantly change, whereas their area significantly increased with age. Nucleocytoplasmic ratio of the LH cells gradually decreased and became significant after the age of 70. Finally, volume density of the FS cell significantly correlated with LH cells area and nucleocytoplasmic ratio. From all above cited, we concluded that in men, density and size of the FS cells increase with age. Long-term hypertrophy of the LH cells results in their functional decline after the age of 70. Strong correlation between FS cells and LH cells morphometric parameters might point to age-related interaction between these two cell groups.

Number of decidual natural killer cells & macrophages in pre-eclampsia

Background & objectives: The process of human placentation is complex and still not well understood. This study was aimed to examine the relationship between clinical features of pre-eclampsia and degree of trophoblastic invasion after its immunohistochemical visualization in the context of possible alterations in the number of natural killer (NK) cells and macrophages in the decidua. Methods: This prospective study included a study group comprising 30 pregnant women with pre-eclampsia delivered by caesarean section and a control group comprising 20 healthy pregnant women also delivered by caesarean section. Samples of placental bed obtained during caesarean section were analyzed after immunohistochemical labelling CD56+ NK cells, CD68+ macrophages and cytokeratin 7 trophoblastic cells. Results: In pre-eclampsia, there was a significantly lower number of CD56+ NK cells in the decidua (P<0.001) and a higher number of CD68+ macrophages (P<0.001) compared to control group. In the subgroup of pre-eclampsia with intrauterine growth retardation (IUGR), a significantly greater number of NK cells (P<0.05) was recorded, as well as an increased number of macrophages, but not significantly compared to pre-eclampsia without IUGR. There was no significant difference in the distribution of these cells in the decidua in relation to the severity of pre-eclampsia. CD56+ NK cells were significantly less (P<0.05) and macrophages were more (P<0.05) in the group with poor trophoblastic invasion. Interpretation & conclusions: Alterations in the number of immune cells in relation to the degree of trophoblastic invasion indicated their role in aetiopathogenesis of pre-eclampsia, while the direct association between their number and severity of pre-eclampsia was not confirmed.

Preeclampsia with and without intrauterine growth restriction–Two pathogenetically different entities?

ABSTRACT Objective: The objective of this study is to determine the differences in histopathological features of basal decidua and placenta in cases of preeclampsia with or without fetal intrauterine growth restriction (IUGR). Methods: A prospective case–control study included a study group consisting of 30 pregnant women with preeclampsia completed by cesarean section (CS), in 19 of whom preeclampsia was associated with IUGR, and in 11 it was not. The control group consisted of 20 healthy pregnant women delivered by elective CS. Placentas and samples of placental bed obtained during CS were histopathologically (HP) analyzed after hematoxylin–eosin staining and immunohistochemical labeling of Cytokeratin 7 (CK7) trophoblastic cells in decidua. Results: Regarding the HP changes in the spiral arteries in preeclampsia, the most frequent features were inadequate transformation of spiral arteries with poor trophoblastic invasion (70.0%) and fibrinoid necrosis of the media (66.7%), and rarely acute atherosis (33.3%) and thrombosis (30.0%). Villous hypermaturity was more frequently found in placentas of patients with preeclampsia with IUGR (p < 0.05), while there were no differences between subgroups of preeclampsia with and without IUGR regarding some of HP alterations of placental bed. Conclusion: Alterations of the placental bed in terms of decidual vasculopathy are more the characteristics of the preeclampsia itself than IUGR, while changes in placental villi primarily follow the presence of IUGR, which could indicate that preeclampsia with and without IUGR are two pathogenetically different entities.

Ameloblastoma of the Lower Jaw: A Case Report

Summary Ameloblastoma, a semi-benign odontogenic tumor, is divided into four subtypes based on the clinical presentation, radiological manifestations and histological characteristics. Radiologically, it manifests itself in the form of uni- or multicystic intrabony expansive lesions, with destruction of the medullary zone of the existing bone, resorption and possible perforation of the buccal and lingual cortex. The patient, a 62-year-old woman, came to the Clinic for Maxillofacial Surgery in Niš with an anamnestically present painless tumefaction in the anterior segment of the mandible present for the past three years. In the course of an intraoral examination in the region of symphysis and parasymphysis of the lower jaw on the left side, an oval-shaped tumor was spotted, 5x3 cm in size; palpation showed that it was hard, painless and motionless. Multislice computed tomography (MSCT) of the oro - and hypopharynx and neck showed an extensive tumor formation of the soft tissue density in the anterior segments of the lower jaw, with the signs of destruction of bone tissue of the buccal and lingual cortex of the lower jaw. The frequency of recurrence depends on the histological type of ameloblastoma and the degree of radicalism of the performed surgical intervention. Ameloblastoma in most cases is definitely diagnosed in the advanced stage of the disease due to the absence of symptoms and very slow tumor progression.

Morphometric analysis of somatotropic cells of the adenohypophysis and muscle fibers of the psoas muscle in the process of aging in humans.

The aim of this research was to quantify changes of the adenohypophyseal somatotropes and types 1 and 2 muscle fibers with aging, as well as to establish mutual interactions and correlations with age. Material was samples of hypophysis and psoas major muscle of 27 cadavers of both genders, aged from 30 to 90 years. Adenohypophyseal and psoas major tissue sections were immunohistochemically processed and stained by anti-human growth hormone and anti-fast myosin antibodies, respectively. Morphometric analysis was performed by ImageJ. Results of morphometric analysis showed a significant increase in the somatotrope area, and significant decrease in somatotrope volume density and nucleocytoplasmic ratio with age. Cross-sectional areas of types 1 and 2, and volume density of type 2 muscle fibers decreased significantly with age. One Way ANOVA showed that the latter cited changes in the somatotropes and types 1 and 2 muscle fibers mostly become significant after the age of 70. Significant positive correlation was observed between the area of the somatotropes and volume density of type 2 muscle fibers. A significant negative correlation was detected between the nucleocytoplasmic ratio of the somatotropes and cross-sectional areas of types 1 and 2 muscle fibers. So, it can be concluded that after the age of 70, there is significant loss of the anterior pituitarys somatotropes associated with hypertrophy and possible functional decline of the remained cells. Age-related changes in the somatotropes are correlated with the simultaneous atrophy of type 1, as well as with the atrophy and loss of type 2 muscle fibers.