Differential expression of CD34 in normal colorectal tissue, peritumoral inflammatory tissue, and tumour stroma

Fibrosis-Related microRNAs in Crohn's Disease with Fibrostenosis and Inflammatory Stenosis

Crohn's disease (CD) is frequently complicated by strictures that can be either inflammatory or fibrostenotic. This distinction is important for deciding the best treatment course, but it can be difficult to determine clinically, sometimes even by advanced imaging techniques. We performed miRNA PCR panel screening on pooled samples of ileum with CD fibrostenosis or inflammatory stenosis. Eight miRNAs with profibrotic (miR-93-5p, miR-376c-3p and miR-424-5p), or fibroprotective (miR-133a-3p, miR-133b, miR-193a-5p, miR-335-5p and miR-378a-3p) functions described in the literature were selected for validation on 20 samples each of CD with fibrostenosis or inflammatory stenosis, with a separate sampling of the submucosa and subserosa. The results showed significant differences between the groups in subserosal samples, with upregulation of profibrotic miRNAs and downregulation of fibroprotective miRNAs in fibrostenosis compared to inflammatory stenosis. Only miR-424-5p showed a significant difference in the submucosa. There were significant differences in miRNA expression between subserosa and submucosa. Our results provide further evidence that the major differences between fibrostenosis and inflammatory stenosis are located in the subserosa, which is inaccessible to endoscopic sampling, highlighting the need for cross-sectional imaging or serological markers. We identify several miRNAs previously not connected to fibrosis in CD, which could potentially serve as biomarkers of fibrostenosis.

Utility of CD34 in Assessing Microvessel Density and Its Correlation With Clinicopathological Parameters in Colorectal Carcinoma Patients

Currently, the most commonly practiced method of reporting cases of colorectal carcinoma is done according to guidelines provided by the College of American Pathologists (8th edition) and the Royal College of Pathologists (UK). These guidelines include various histopathological parameters like tumor site, extent, histologic type, grade, margins, tumor budding, lymphovascular invasion, and perineural invasion. However, in the present guidelines, the immunohistochemistry-based marker of mean vessel density (MVD) has not been addressed as an important parameter. The present study gives an overview of the importance of MVD. MVD was statistically significant when correlated with tumor size, lymph node metastasis, grade, and vascular invasion. However, no statistical significance was observed when compared with age, perineural invasion, and stage of the tumor.

Preliminary study of some of the main intratumor stroma components in gastric carcinomas

AIM

The relationship between stromal compartment and tumor behavior in gastric carcinomas is still poorly understood and defined. Therefore, the authors started, with this preliminary study, an analysis of stromal compartment morphology and behavior in tumors arising from gastric mucosa epithelium.

MATERIALS AND METHODS

The study group included 75 patients operated for gastric carcinoma. Five parameters describing tumor morphology and behavior and eight parameters describing tumor stroma (TS) morphology were assessed. Histopathological examination included six serial sections of formalin-fixed, paraffin-embedded tumor tissue samples, stained with three classical stains and three antibodies to reveal the different parameters. For data comparison, Pearson's correlation test and the chi-squared (χ²) correlation test were used.

RESULTS

Studied tumors were, usually, infiltrating, undifferentiated∕diffuse type, invasive in subserous spaces and with a Ki67 index higher than 20%. Collagen fibers dominated the stromal components, with a predominance of mature type and an average fibrillary index of 2.7. The whole amount of stromal components accounted for around one quarter of the tumor area. Mature collagen fibers were in opposite correlation with their immature counterpart, and both were in opposite correlation with smooth muscle fibers and expressed an opposite trend of correlation with components of vascular compartment. The whole amount of stromal components had divergent behavior with the components of vascular compartment. The latter expressed generally an opposite trend of correlation with individual fibrillary stromal components. We found only isolated relationships statistically significant between stromal components and tumor characteristics.

CONCLUSIONS

TS is in a continuous remodeling process in relation to the evolution of tumor parenchyma, tumors less differentiated proving to have an immature stroma, with newly formed collagen fibers and higher vascular density. Further studies are required.

Interstitial Cells of Cajal-Origin, Distribution and Relationship with Gastrointestinal Tumors

The interstitial cells of Cajal (ICC) represent a particular network formed by some peculiar cells that were first described by the great neuroanatomist, S. Ramon y Cajal. Nowadays, the ICC have become a fascinating topic for scientists, arousing their curiosity; as a result, there is a vast number of published articles related to the ICC. Today, everybody widely accepts that the ICC represent the pacemaker of the gastrointestinal tract and are highly probable to be the origin cells for gastrointestinal tumors (GISTs). Recently, Cajal-like cells (ICLC) were described, which are found in different organs but with an as yet unknown physiological role that needs further study. New information regarding intestinal development indicates that the ICC (fibroblast-like and muscle-like) and intestinal muscle cells have the same common embryonic cells, thereby presenting the same cellular ultrastructure. Nowadays, there is a vast quantity of information that proves the connection of the ICC and GISTs. Both of them are known to present c-kit expression and the same ultrastructural cell features, which includes minimal myoid differentiation that is noticed in GISTs, therefore, supporting the hypothesis that GISTs are ICC-related tumors. In this review, we have tried to highlight the origin and distribution of Cajal interstitial cells based on their ultrastructural features as well as their relationship with gastrointestinal stromal tumors.

The Long Telling Story of "Endothelial Progenitor Cells": Where Are We at Now?

Endothelial progenitor cells (EPCs): The name embodies years of research and clinical expectations, but where are we now? Do these cells really represent the El Dorado of regenerative medicine? Here, past and recent literature about this eclectic, still unknown and therefore fascinating cell population will be discussed. This review will take the reader through a temporal journey that, from the first discovery, will pass through years of research devoted to attempts at their definition and understanding their biology in health and disease, ending with the most recent evidence about their pathobiological role in cardiovascular disease and their recent applications in regenerative medicine.

Increased CD34 in pancreatic islet negatively predict islet β-cell decrease in type1 diabetes model

Islet β-cell biomarkers can reflect changes in the number and function of islet β-cells in the prediabetes or early diabetes stage. CD34 is a commonly used stem cell biomarker; however, its expression and function in pancreatic islets remain unclear. In the present study, double immunofluorescence staining, proteomic bioinformatics analysis, and correlation analysis were used to explore the potential of CD34 as an islet β-cell biomarker. Bioinformatics analysis revealed that the amino acid sequence of CD34 was conserved among multiple species and abundantly expressed on mouse and human pancreatic tissues. Immunofluorescence demonstrated that in the control rat pancreas, CD34 was expressed on glucagon-labeled islet α-cells but not on insulin-labeled islet β-cells. Furthermore, the proportion of CD34-positive cells, which were also positive for glucagon, was significantly increased in alloxan-induced diabetes models. Statistical analysis revealed that the expression of CD34 was negatively correlated with the number of insulin-labeled islet β-cells during diabetes progression in dose-dependent fashion in alloxan-induced diabetes models. Furthermore, the results suggested that the transdifferentiation of islet β-cells into islet α-cells may occur in the process of diabetes. Thus, the present study demonstrated that CD34 is expressed on islet α-cells, and its number is linearly and negatively correlated with the number of islet β-cells, suggesting that CD34 can be used as a prospective biomarker for islet β-cells in the early diagnosis of diabetes. The study also suggests the transformation of β-cells to α-cells in diabetes which provide a potential to be applied towards diabetes mechanism research.

Nestin and CD34 expression in colorectal cancer predicts improved overall survival

BACKGROUND

Nestin, a class VI intermediate filament protein of the cytoskeleton, and CD34, a transmembrane phosphoglycoprotein, are markers of progenitor cells. This study aimed to evaluate their expression and clinical significance in colorectal cancer.

METHODS

A clinically annotated tissue microarray, including 599 patients with colorectal cancer, was analyzed by immunohistochemistry. Furthermore, nestin and CD34 correlations with HIF-1a and a panel of cytokines and chemokines were assessed using quantitative reverse transcription PCR and The Cancer Genome Atlas dataset.

RESULTS

Expression of nestin and CD34 was observed only in the tumor stroma. Patients displaying high expression of nestin and CD34 demonstrated higher rates of T1 and T2 tumors (p = .020), lower vascular invasion (p < .001) and improved 5-year overall survival (65%; 95% CI = 55-73 vs 45%; 95% CI = 37-53) after adjusting for clinicopathological characteristics (HR: 0.67; 95% CI = 0.46-0.96). A moderate to strong correlation (r = 0.37-0.78, p < .03) of nestin and CD34 was demonstrated for the following markers; HIF-1α, CD4, CD8, FOXP3, IRF1, GATA3, CCL2, CCL3, CXCL12 and CCL21.

CONCLUSIONS

Combined expression of nestin and CD34 expression is associated with better overall survival possibly by modulating a favorable immune response.

CD34+ Stromal Cells/Telocytes as a Source of Cancer-Associated Fibroblasts (CAFs) in Invasive Lobular Carcinoma of the Breast

Several origins have been proposed for cancer-associated fibroblasts (CAFs), including resident CD34+ stromal cells/telocytes (CD34+SCs/TCs). The characteristics and arrangement of mammary CD34+SCs/TCs are well known and invasive lobular carcinoma of the breast (ILC) is one of the few malignant epithelial tumours with stromal cells that can express CD34 or αSMA, which could facilitate tracking these cells. Our objective is to assess whether tissue-resident CD34+SCs/TCs participate in the origin of CAFs in ILCs. For this purpose, using conventional and immunohistochemical procedures, we studied stromal cells in ILCs (n:42) and in normal breasts (n:6, also using electron microscopy). The results showed (a) the presence of anti-CD34+ or anti-αSMA+ stromal cells in varying proportion (from very rare in one of the markers to balanced) around nests/strands of neoplastic cells, (b) a similar arrangement and location of stromal cells in ILC to CD34+SCs/TCs in the normal breast, (c) both types of stromal cells coinciding around the same nest of neoplastic cells and (d) the coexpression of CD34 and αSMA in stromal cells in ILC. In conclusion, our findings support the hypothesis that resident CD34+SCs/TCs participate as an important source of CAFs in ILC. Further studies are required in this regard in other tumours.

Expression of CD34 and α-SMA Markers in Oral Squamous Cell Carcinoma Differentiation. A Histological and Histo-Chemical Study

To reduce morbidity and mortality rates of OSCC cases, early diagnosis, assessment of behavior and prognostic estimates are vital. This study analyzed the expression of CD34 and alpha smooth muscle actin (α-SMA) in OSCC, to establish their significance in diagnosis and prognosis. Primary cases of OSCC, diagnosed with excisional biopsy at multiple cancer treatment centers, were included. Tissue sections were embedded and stained with H & E for histological differentiation and invasion of tumor vessel. Immunohistochemistry was performed using antibodies against CD34 and α-SMA. The chi-square and Pearson correlation coefficient (r) tests were applied for data analysis. Eighty patients with fifty males (62.5%) and thirty females (37.5%) and mean age of 45 ± 14.1 years were evaluated. Buccal mucosa was the most common site for OSCC lesions [36 (45%)]; 47.5% of lesions were moderately differentiated and 33.8% were well-differentiated lesions. Invasion of tumor vessels was observed in 35% of specimens. A significant association was seen between CD34 expression and histological grading of OSCC (p < 0.002). Among all poorly differentiated OSCC specimens, expression of CD 34 was low and α-SMA was high. CD 34 is a critical prognostic factor in OSCC diagnosis and increased α-SMA-positive myofibroblasts may indicate aggressive OSCC behavior.

Presence/Absence and Specific Location of Resident CD34+ Stromal Cells/Telocytes Condition Stromal Cell Development in Repair and Tumors

CD34+ stromal cells/telocytes (CD34+SCs/TCs) can have a role as mesenchymal precursor cells. Our objective is to assess whether the myofibroblastic stromal cell response in repair and in desmoplastic reactions in tumors depend on the presence or absence of resident CD34+SCs/TCs in specific regions/layers of an organ and on the location of their possible subpopulations. For this purpose, using conventional and immunohistochemical procedures, we studied specimens of (a) acute cholecystitis, with early repair phenomena (n: 6), (b) surgically resected segments of colon tattooed with India ink during previous endoscopic removal of malignant polyps, with macrophage infiltration and stromal cell reaction (n: 8) and (c) infiltrative adenocarcinomas of colon, with desmoplastic reaction (n: 8). The results demonstrated (a) stromal myofibroblastic reaction during repair and tumor desmoplasia in most regions in which resident CD34+SCs/TCs are present, (b) absence of stromal myofibroblastic reaction during repair in the mucosa of both organs in which resident CD34+SCs/TCs are absent and (c) permanence of CD34+SCs/TCs as such, without myofibroblastic response, in smooth muscle fascicles, nerves, and Meissner and Auerbach plexuses, in which the CD34+SCs/TCs mainly undergo reactive phenomena. Therefore, the development of activated αSMA+ myofibroblasts in these conditions requires the presence of resident CD34+SCs/TCs and depends on their location. In conclusion, the facts support the hypotheses that CD34+SCs/TCs participate in the origin of myofibroblasts during repair and tumor stroma formation, and that there is a heterogeneous population of resident CD34+SCs/TCs with different roles.

Lack of CD34 produces defects in platelets, microparticles, and lung inflammation

Lung innate immune activation results in acute lung inflammation, which is characterized by alveolar barrier disruption and accumulation of cellular lung aggregates comprising neutrophils, platelets, mononuclear cells, and microparticles. CD34 is a sialomucin, with pan-selectin affinity and recently shown to protect the endothelial barrier in a bleomycin-induced lung injury model. However, there is very little information about the fundamental role of CD34 in regulation of the lung innate immune response. We hypothesized that CD34 regulates leukocyte recruitment by promoting optimal platelet activation (aggregation and spread) during bacterial lipopolysaccharide (LPS)-induced acute lung injury. Therefore, we utilized CD34 knock-out (KO) and wild-type (WT) mice to analyze and compare the morphology and expression of leukocyte subsets from the pulmonary and systemic compartments. We utilized the chemotactic N-formylated tri-peptide, fMLP, to understand platelet aggregation in vitro, and the fundamental immune stimulant, LPS, to induce lung injury and understand platelet activation ex vivo. Our data reveal that under steady-state conditions, KO mice possess large aggregates of integrin β₃ (CD61)-positive microparticles in peripheral blood. Moreover, the KO mice recruit a large number of neutrophils to lungs, which are not cleared even at 36-h post-LPS exposure. The KO mice display an increased platelet CD61 expression, which aggregates, but does not spread normally in response to in vitro fMLP treatment. The KO platelets display similar deficits in their spreading ability even after ex vivo LPS exposure. Thus, our data demonstrate that CD34 modulates platelet biology, microparticle aggregation, and neutrophil recruitment during murine lung inflammation.

Role of VEGF, CD105, and CD31 in the Prognosis of Colorectal Cancer Cases

INTRODUCTION

Colorectal cancer (CRC) incidence is increasing globally. It is ranked as the second most common cancer in women and the third most in men. Angiogenesis plays a significant role in the development and spread of colorectal cancer. Angiogenesis has been proposed as a prognostic marker in a variety of human neoplasms. In this regard, markers of angiogenic endothelial cells are emerging as targets for cancer therapy.

AIM OF THE WORK

The aim of this study is to evaluate the prognostic impact of tumor angiogenesis assessed by microvessel density (MVD) counting using CD31 and CD105 along with VEGF immunostaining in colorectal cancer patients.

METHODS

VEGF, CD31, and CD105 expressions were evaluated using immunohistochemical staining in 50 patients with colorectal cancer. The relationship between their expressions and clinicopathological factors and outcome of patients were analyzed.

RESULTS

The VEGF expression (70% of the cases) correlated significantly with larger tumor size, higher grade, and advanced tumor stage (p = 0.006, p < 0.001, p < 0.001), respectively. The mean MVD was 24.2 ± VMD by CD105 (p = 0.10.65 019 for CD105, 19.2 ± 8.41 for CD31, respectively. MVD by CD31 (p = 0.023)) and was significant predictive factors for overall survival. Furthermore, the VEGF expression (p = < 0.001) was a significant predictive factor for DFS. There was a statistically significant association between the recurrence rates with both VEGF and CD105 (p < 0.001) but not significant with CD31.

CONCLUSION

CRC patients with high VEGF, CD105, and CD31 expression showed poor prognosis. The immunohistochemical markers could be used for stratification of patients into low-risk and high-risk groups.

Clinicopathological study of role of CD34 expressions in the stroma of premalignant and malignant lesions of uterine cervix

CD34 is a transmembrane glycoprotein that is thought to be involved in the modulation of cell adhesion and signal transduction. The connective tissue stroma of virtually all human organs contain large amounts of resident CD34+ fibrocytes, which are involved in multiple functions such as wound healing, secretion of cytokines and also participate in stromal remodeling. It has been seen in various studies that absence of CD34+ fibrocytes within the stroma is associated with invasive carcinomas. In our study, we also investigated the presence and distribution of CD34+ fibrocytes in cervical intraepithelial neoplasia, invasive cervical carcinoma and adjacent normal cervical stroma. It was seen that normal cervical stroma and the stroma adjacent to cervical intra epithelial lesions harbours a dense meshwork of CD34+ fibrocytes, whereas the stroma of invasive carcinoma was nearly devoid of this cell population. Early stromal invasion by squamous carcinoma was characterized by a focal loss of CD34+ fibrocytes. This can be used as a sensitive tool in detecting tiny foci of stromal invasion in early cancer.

Clinicopathological significance of cancer-associated fibroblasts in papillary thyroid carcinoma: a predictive marker of cervical lymph node metastasis

PURPOSE

Most tumors have obvious biologically active fibroblasts known variously as myofibroblasts or cancer-associated fibroblasts (CAFs) in the stroma. CAFs have been known as an important factor of cancer invasion and metastasis. This study aimed to investigate the presence of CAFs in patients with papillary thyroid carcinoma (PTC) and evaluate the correlation between CAFs and cervical lymph node (LN) metastasis in PTC through immunohistochemistry.

METHODS

The medical records of 128 patients who were diagnosed with PTC from January 1, 2010 to December 31, 2010 were reviewed, and 78 patients who underwent total thyroidectomy with or without neck dissection, were included in this study. A retrospective pathological evaluation was performed to verify the presence of CAFs. CD34 and α-smooth muscle actin (SMA) were used as markers of CAFs.

RESULTS

Among 78 patients with PTC, 65 had desmoplastic stromal reaction around the PTC. Through immunohistochemical study of anti-CD34 and α-SMA antibodies, CAFs were found in 42 (64.6%) cases with desmoplastic stroma around the PTC. Univariate analysis showed that tumor size and CAFs were the risk factors of LN metastasis in patients with PTC, while multivariate analysis revealed that CAFs were the only independent risk factor of LN metastasis in patients with PTC.

CONCLUSION

This study revealed the presence of CAFs in PTC. Furthermore, CAFs were found to be a risk factor of LN metastasis in PTC. Therefore, CAFs may be used as a predictive marker for LN metastasis in patients with PTC.

Behaviour of telocytes during physiopathological activation

We consider CD34+ stromal cells/telocytes (CD34+ SC/TCs) in normal and pathological conditions. These cells are involved in organisation and control of the extracellular matrix, structural support, creation of microenvironments, intercellular communication, neurotransmission, immunomodulation and immunosurveillance, inhibition of apoptosis, and control, regulation and source of other cell types. CD34+ SC/TCs are widely reported in the origin of interstitial cells of Cajal and in regeneration in the heart, skeletal muscle, skin, respiratory tree, liver, urinary system and the eye. In addition, we contribute CD34+ SC/TC hyperplasia associated with several processes, including neurogenous hyperplasia (neuroma of the appendix), hyperplasia of Leydig cells in undescended testes (Cryptorchidism), peripheral areas of inflammatory/repair processes (pericicatricial tissue and transitional zones between diseased segments in Crohn's disease and normal bowel), benign tumours (neurofibromas, Antoni-B zones of neurilemmomas, granular cell tumours, and melanocytic nevi) and in some lesions with myxoid, oedematous and degenerative changes (Reinke's oedema, myxomatous mitral valve degeneration, thyroid-associated ophthalmopathy and basophilic degenerative changes of the collagen in the dermis). We pay particular attention to the role of CD34+ SC/TCs during repair through granulation tissue, including morphologic changes, loss of CD34 expression and gain of αSMA expression with myofibroblast transformation, and interactions with pericytes, endothelial and inflammatory cells. Finally, we consider CD34 or αSMA expression in stromal cells of malignant epithelial tumours, and the role of CD34+ SC/TCs in the origin of carcinoma-associated fibroblasts (CAFs) and myofibroblasts. In conclusion, CD34+ SC/TCs play an important role in the maintenance and modulation of tissue homeostasis and in morphogenesis/renewal/repair.

Concise review: evidence for CD34 as a common marker for diverse progenitors

CD34 is a transmembrane phosphoglycoprotein, first identified on hematopoietic stem and progenitor cells. Clinically, it is associated with the selection and enrichment of hematopoietic stem cells for bone marrow transplants. Due to these historical and clinical associations, CD34 expression is almost ubiquitously related to hematopoietic cells, and it is a common misconception that CD34-positive (CD34⁺) cells in nonhematopoietic samples represent hematopoietic contamination. The prevailing school of thought states that multipotent mesenchymal stromal cells (MSC) do not express CD34. However, strong evidence demonstrates CD34 is expressed not only by MSC but by a multitude of other nonhematopoietic cell types including muscle satellite cells, corneal keratocytes, interstitial cells, epithelial progenitors, and vascular endothelial progenitors. In many cases, the CD34⁺ cells represent a small proportion of the total cell population and also indicate a distinct subset of cells with enhanced progenitor activity. Herein, we explore common traits between cells that express CD34, including associated markers, morphology and differentiation potential. We endeavor to highlight key similarities between CD34⁺ cells, with a focus on progenitor activity. A common function of CD34 has yet to be elucidated, but by analyzing and understanding links between CD34⁺ cells, we hope to be able to offer an insight into the overlapping properties of cells that express CD34. Stem Cells2014;32:1380–1389

Telocytes are reduced during fibrotic remodelling of the colonic wall in ulcerative colitis

Ulcerative colitis (UC) is characterized by chronic relapsing intestinal inflammation finally leading to extensive tissue fibrosis and resulting in a stiff colon unable to carry out peristalsis or to resorb fluids. Telocytes, a peculiar type of stromal cells, have been recently identified in the human gastrointestinal tract. Several roles have been proposed for telocytes, including mechanical support, intercellular signalling and modulation of intestinal motility. The aim of the present work was to investigate the presence and distribution of telocytes in colonic specimens from UC patients compared with controls. Archival paraffin-embedded samples of the left colon from UC patients who underwent elective bowel resection and controls were collected. Tissue sections were stained with Masson's trichrome to detect fibrosis. Telocytes were identified by CD34 immunohistochemistry. In early fibrotic UC cases, fibrosis affected the muscularis mucosae and submucosa, while the muscularis propria was spared. In advanced fibrotic UC cases, fibrosis extended to affect the muscle layers and the myenteric plexus. Few telocytes were found in the muscularis mucosae and submucosa of both early and advanced fibrotic UC colonic wall. In the muscle layers and myenteric plexus of early fibrotic UC, telocytes were preserved in their distribution. In the muscularis propria of advanced fibrotic UC, the network of telocytes was reduced or even completely absent around smooth muscle bundles and myenteric plexus ganglia, paralleling the loss of the network of interstitial cells of Cajal. In UC, a loss of telocytes accompanies the fibrotic remodelling of the colonic wall and might contribute to colonic dysmotility.

Vasculo-smooth muscle hamartomatous structure is linked to morphogenesis of colorectal polypoid adenoma

To investigate the difference of surrounding stromal structure between the polypoid and flat adenomas in the colorectum, we performed microscopic study including immunohistochemistry in a total of 32 colorectal adenomas (typical 24 polypoid and eight flat adenomas), especially focusing on vessels around muscularis mucosa. All 24 polypoid adenomas accompanied vasculo-smooth muscle hamartomatous structure in association with muscularis mucosa and submucosal vessels, whereas none of eight flat adenomas had vasculo-smooth muscle hamartomatous structure; surrounding muscularis mucosa and submucosa of the flat adenomas are identical to those of normal colorectal tissue. Vasculo-smooth muscle hamartomatous structure is linked to the morphogenesis of colorectal polypoid adenomas.

Diagnostic and prognostic impact of peritumoral stromal remodeling in patients with surgically treated invasive penile squamous cell cancer

Stromal remodeling (SR), characterized by focal loss of CD34(+) fibrocytes paralleled by a gain of α-smooth muscle actin (α-SMA)-positive myofibroblasts, has been reported in several cancer types. However, the role of SR in invasive penile squamous cell cancer (PSC) has not been investigated so far. We compared 90 surgically treated PSCs (study group) and 55 control specimens (33 foreskins and 22 differentiated penile intraepithelial neoplasias) for the presence of stromal CD34(+) fibrocytes and α-SMA-positive myofibroblasts scored by independent raters. Multivariate proportional hazards regression analysis was used to assess the impact of staining profiles on cancer-specific mortality of the 90 PSCs (median follow-up, 32 months; interquartile range, 6-64). The incidence of SR differed significantly between study and control group specimens (51.1% versus 9.1%; P < .001). Five years postsurgically, 24% and 46% of the study patients without and with SR had succumbed to their PSC (P = .010). After adjusting for the age at the time of surgery, type of surgery, tumor size, Broders' grade, pT stage, and nodal status, study patients with SR showed 3.76-fold increased cancer-specific mortality (95% confidence interval, 1.3-10.5; P = .012). Our findings suggest that SR might have prognostic as well as some limited differential diagnostic value in terms of delineating invasive PSC from preinvasive lesions. However, our preliminary data clearly need to be validated by larger advanced studies in the future.

Dermal mast cells affect the development of sunlight-induced skin tumours

Ultraviolet (UV) radiation contained in sunlight is considered a major risk in the induction of skin cancer. While mast cells are best known for their role in allergic responses, they have also been shown to play a crucial role in suppressing the anti-tumour immune response following UV exposure. Evidence is now emerging that UV may also trigger mast cell release of cutaneous tissue remodelling and pro-angiogenic factors. In this review, we will focus on the cellular and molecular mechanisms by which UV recruits and then activates mast cells to initiate and promote skin cancer development.

Expression and role of fibroblast activation protein-alpha in microinvasive breast carcinoma

BACKGROUND

Diagnosis of ductal carcinoma in situ (DCIS) in breast cancer cases is challenging for pathologist due to a variety of in situ patterns and artefacts, which could be misinterpreted as stromal invasion. Microinvasion is detected by the presence of cytologically malignant cells outside the confines of the basement membrane and myoepithelium. When malignant cells invade the stroma, there is tissue remodeling induced by perturbed stromal-epithelial interactions. Carcinoma-associated fibroblasts (CAFs) are main cells in the microenvironment of the remodeled tumor-host interface. They are characterized by the expression of the specific fibroblast activation protein-alpha (FAP-α), and differ from that of normal fibroblasts exhibiting an immunophenotype of CD34. We hypothesized that staining for FAP-α may be helpful in determining whether DCIS has microinvasion.

METHODS

349 excised breast specimens were immunostained for smooth muscle actin SMA, CD34, FAP-α, and Calponin. Study material was divided into 5 groups: group 1: normal mammary tissues of healthy women after plastic surgery; group 2: usual ductal hyperplasia (UDH); group 3: DCIS without microinvasion on H & E stain; group 4: DCIS with microinvasion on H & E stain (DCIS-MI), and group 5: invasive ductal carcinoma (IDC). A comparative evaluation of the four immunostains was conducted.

RESULTS

Our results demonstrated that using FAP-α and Calponin adjunctively improved the sensitivity of pathological diagnosis of DCIS-MI by 11.29%, whereas the adjunctive use of FAP-α and Calponin improved the sensitivity of pathological diagnosis of DCIS by 13.6%.

CONCLUSIONS

This study provides the first evidence that immunostaining with FAP-α and Calponin can serve as a novel marker for pathologically diagnosing whether DCIS has microinvasion.

Tissue remodelling in breast cancer: human mast cell tryptase as an initiator of myofibroblast differentiation

AIMS

Cancerogenesis is characterized by increase of differentiated myofibroblasts. Mast cells (MCs) exert powerful effects on fibroblasts through a variety of mediators. We investigated α-smooth-muscle actin (α-SMA(+) ) and CD34(+) fibroblasts, density of toluidine blue-stained (MCs-TB) and tryptase-immunolabelled MCs (MCs-Try) in 30 primary breast tumours.

METHODS AND RESULTS

Tumour (T), peri-tumoral (PT) and non-tumoral (NT) tissue was studied by immunohistochemistry and electron microscopy. MCs-TB and MCs-Try increased gradually from NT to PT and T and the comparison between the three compartments varied significantly. Degranulated MCs were present more significantly in NT and adjacent PT than T. Transition between NT, PT and T was marked by increasing α-SMA(+) fibroblasts and slow disappearance of CD34(+) stromal cells. In NT, CD34(+) fibroblasts correlated with low density both of MCs-TB and intact MCs-Try (P=0.0346 and P=0.0409, respectively). In T, the few preserved CD34(+) fibroblasts were associated with low-density degranulated MCs-Try (P=0.0173). The α-SMA(+) fibroblasts correlated with high density of intact MCs-Try in PT, and with high density of degranulated MCs-Try in T (P=0.0289), also confirmed by ultrastructural analysis.

CONCLUSIONS

This preliminary investigation suggests that during breast cancer progression the MCs may contribute to stromal remodelling and differentiation of myofibroblasts, through tryptase released in stromal microenvironment.

CD34-positive stem cells: in the treatment of heart and vascular disease in human beings

Bone marrow-derived CD34(+) cells are a well-characterized population of stem cells that have traditionally been used clinically to reconstitute the hematopoietic system after radiation or chemotherapy. More recently, CD34(+) cells have also been shown to induce therapeutic angiogenesis in animal models of myocardial, peripheral, and cerebral ischemia. The mechanism by which CD34(+) cells promote therapeutic angiogenesis is not completely understood, although evidence supports both direct incorporation of the cells into the expanding vasculature and paracrine secretion of angiogenic growth factors that support the developing microvasculature. Phase I and phase II clinical trials have explored the usefulness of CD34(+) cells in the treatment of ischemic conditions in human patients. As the population of patients diagnosed with some form of ischemic cardiovascular disease expands, the need for more effective treatments also grows, especially in patients who are refractory to standard pharmacologic or revascularization treatment. As phase III trials begin, CD34(+) cells will be definitively tested as a novel treatment for myocardial and peripheral ischemia. This review will discuss what is known about the CD34 antigen and the cells that harbor it, the preclinical evidence supporting the therapeutic potential of CD34(+) cells in ischemic models, and, last, the current evidence for the clinical usefulness of CD34(+) cells in the treatment of human ischemic disease.

Expression of CD34, alpha-smooth muscle actin and transforming growth factor-beta1 in squamous intraepithelial lesions and squamous cell carcinoma of the cervix

This retrospective study investigated CD34, alpha-smooth muscle actin (alpha-SMA), and transforming growth factor-beta1 (TGF-beta1) expression in stromal cells of cervical intraepithelial neoplasias (CINs; n = 30), invasive cervical squamous cell carcinomas (SCCs; n = 38) and adjacent normal cervix. Normal cervix and CINs contained diffuse CD34-positive stromal cells but no alpha-SMA-positive myofibroblasts. In contrast, 34 of 38 SCCs were free of CD34-positive stromal cells and all contained alpha-SMA-positive stromal myofibroblasts; adjacent normal tissue contained CD34-positive stromal cells and no alpha-SMA-positive myofibroblasts. More intense TGF-beta1 expression was observed in SCC cells than in normal cervical epithelium or CINs. This study shows that the disappearance of CD34-positive stromal cells and appearance of alpha-SMA-positive stromal myofibroblasts may be associated with transformation of cervical CIN to SCC. These findings support the suggestion that over-production of TGF-beta1 in SCC cells is one potential mechanism mediating the transformation of stromal cells to myofibroblasts in cervical carcinogenesis.

J. Expressão citofotométrica dos marcadores tumorais CD-34 e fator VIII no câncer de cólon

OBJETIVOS: Verificar a posssibilidade de quantificar a expressão dos marcadores tumorais CD-34 e Fator VIII no câncer de cólon; verificar se existe superioridade entre um marcador e outro para estudo da angiogênese; verificar se há correlação na análise do índice de marcagem e a densidade óptica média nos marcadores utilizados. MÉTODOS: Dezessete casos de adenocarcinoma colorretal recuperados de blocos de parafina e confirmados pela hematoxilina-eosina, foram submetidos à coloração imunoistoquímica pelo método da estreptoavidina-biotina-peroxidase e utilizados os marcadores tumorais CD-34 e Fator VIII. Após este processo as lâminas foram submetidas à leitura no sistema Samba 4000® e avaliadas pelo software Immuno®. Os parâmetros estudados foram: índice de marcagem e densidade óptica, expressos por médias, medianas, valores mínimos, valores máximos e desvios-padrão, analisados estatisticamente. RESULTADOS: Para o marcador CD-34 não houve normalidade dos dados em relação ao índice de marcagem e houve para a densidade óptica. Para o Fator VIII, houve normalidade de dados em relação ao índice de marcagem e para a densidade óptica. CONCLUSÃO: Foi possível quantificar a expressão dos marcadores tumorais CD-34 e Fator VIII através do índice de marcagem e da densidade óptica média; não houve diferença entre os marcadores em relação à média do índice de marcagem e da densidade óptica, não sendo possível definir superioridade entre um e outro; não foi observada tendência à correlação quando comparados densidade óptica e índice de marcagem do Fator VIII e do CD-34 isoladamente estudados; não houve correlação entre o índice de marcagem do Fator VIII quando comparado com o CD-34, bem como a densidade óptica do Fator VIII com o CD-34.

CD34(+) fibrocytes in melanocytic nevi and malignant melanomas of the skin

CD34(+) fibrocytes are constitutive elements of the human connective tissue. The stroma associated with invasive carcinomas is characterized by a stereotypic loss of CD34(+) fibrocytes and a phenotype change towards CD34(-) alpha-Smooth muscle actin (SMA)(+) myofibroblasts. Secreted protein acidic and rich in cysteine (SPARC) is an important mediator of tumor-associated stromal remodeling. Melanocytic lesions of the skin have not been investigated as to this aspect up to now. Thus, we investigated a total of 20 malignant melanomas and 29 melanocytic nevi. The normal dermis and benign melanocytic nevi showed numerous CD34(+) fibrocytes, whereas malignant melanomas were devoid of this cell type. alpha-SMA-positive myofibroblasts were absent from the normal dermis, melanocytic nevi, and malignant melanomas. SPARC was positive in malignant melanoma cells and negative in their associated stroma, while all melanocytic nevi were completely negative. The stromal phenotype of malignant melanomas (CD34(-) alpha-SMA(-)) differs from that of invasive carcinomas (CD34(-) alpha-SMA(+)) suggesting different pathogenic mechanisms involved in tumor-associated stromal remodeling. SPARC expression appears to be closely related to malignancy in melanocytic lesions.

CD34-positive dendritic cells disappear from scars but are increased in pericicatricial tissue

CD34-positive stromal cells (CD34SC) are distributed throughout the body, including the dermis. They are thought to play a role in maturation and proliferation of adjacent mesenchymal and epithelial stem cells and in immune responses. To investigate the role of such cells in wound healing after excision of cutaneous lesions, we examined the distribution and quantity of CD34SC in scars from the sites of removal of malignant skin tumors and from reconstructive surgery, as well as in samples of normal skin. In normal skin, CD34 staining was confined to dendritic cells in the dermis, endothelial cells, perifollicular cells and eccrine glands. In cutaneous scars, the cicatricial tissue was totally devoid of CD34SC. However, the dermis adjacent to scar showed increased numbers of CD34SC as compared with normal skin [41.5 cells/mm(2) vs. 24.5 cells/mm(2) (p < 0.001)]. We conclude that CD34SC disappears from scars but are induced to proliferate in pericicatricial tissue. The cells in question may play a role in remodeling of scarred skin. One should be aware that augmented labeling for CD34SC around scars is common; it should not be interpreted as evidence for the persistence or recurrence of tumors that may also express CD34.

A novel population of repair cells identified in the stroma of the human cornea

The transmembrane protein CD133 is expressed on somatic stem cells of various adult human tissues. To investigate whether human corneal stroma also contains CD133-expressing cells and to analyze their functional features, stromal cells were isolated by collagenase digestion, immunophenotyped, and transferred to different culture systems to determine their stem cell properties as well as their differentiation potentials. For comparison, the embryonic keratocyte cell line EK1.Br, the dermal stromal cell line NHDF, and stromal cells of diseased corneas were studied. On average, 5.3% of the normal stromal cells expressed the stem cell marker CD133 and 3.6% co-expressed CD34. Expression of CD133 but not CD34 was also demonstrated for EK1.Br cells, whereas NHDF cells were negative for both markers. Further analysis of CD133(+) normal corneal cells revealed that a significant proportion displayed a monocytic phenotype with co-expression of CD45 and CD14. In diseased corneas, up to 26.8% of the stromal cells showed expression of CD133, and virtually all CD133(+) cells co-expressed CD14 but not CD45. Moreover, using a standard clonogenic assay, normal stromal cells had the capacity to form colonies of the macrophage lineage. These colonies could be further differentiated into lumican-expressing keratocytes. Our data suggest that the human corneal stroma harbors CD133(+) monocytic progenitor cells, which possess the potential to differentiate into the fibrocytic lineage. Thus, CD133(+) /CD45(+) /CD14(+) cells might represent stromal repair cells that differentiate into keratocytes via a CD133(+)/CD45()/CD14(+) intermediate stage. The findings from our study may shed new light on regenerative processes of the human corneal stroma.

CD34+ fibrocytes in chronic cystitis and noninvasive and invasive urothelial carcinomas of the urinary bladder

CD34+ fibrocytes are constitutive elements of the connective tissue where they play a role in matrix synthesis and tumor-associated stromal remodeling. Secreted protein, acidic, and rich in cysteine (SPARC) is a pivotal mediator of stromal remodeling precipitated by invasive carcinomas. The present study was undertaken to investigate CD34+ fibrocytes in the stroma of the tumor-free urinary bladder, chronic cystitis, and urothelial carcinomas together with stromal expression of alpha-smooth muscle actin (alpha-SMA), CD117, and SPARC. In tumor-free urinary bladder and chronic cystitis, CD34+ fibrocytes were found in the deep lamina propria and tunica muscularis, whereas the superficial lamina propria disclosed a CD34-negative and alpha-SMA-positive fibrocyte-like cell. Invasive urothelial carcinomas revealed a complete loss of CD34+ fibrocytes and concomitant appearance of alpha-SMA-reactive myofibroblasts which showed strong expression of SPARC. CD117 expression of tumor-free and tumor-associated stroma revealed no differences. We in this study for the first time describe CD34+ fibrocytes in the urinary bladder and an up-to-now unknown population of alpha-SMA-positive fibrocytes exclusively occurring in the superficial lamina propria. Stromal remodeling associated with invasive carcinomas in the urinary bladder is characterized by a loss of CD34+ fibrocytes paralleled by a gain of alpha-SMA-positive myofibroblasts and increased expression of SPARC.

CD34+ fibrocytes are preserved in most invasive lobular carcinomas of the breast

It is generally agreed that invasive carcinomas of the breast consistently lack stromal CD34+ fibrocytes. The pertinent literature shows that this assumption is well based for invasive ductal carcinomas, but evidence of loss of stromal CD34+ cells in lobular carcinomas is weak. We present a series of 22 invasive lobular carcinomas (ILCs) which, in contrast to invasive ductal carcinomas, display a gradual reduction of stromal CD34+ fibrocytes. One third of the study population showed a completely preserved population of CD34+ fibrocytes, in another third, this cell population was reduced in comparison to normal breast tissue, and in the remaining third, loss of CD34+ fibrocytes comparable to that occurring in virtually all invasive ductal carcinomas was found. The present study shows that loss of CD34+ fibrocytes is not a consistent feature of invasive carcinomas of the breast. Therefore, a preserved CD34+ stromal cell population does not exclude malignancy, and analysis of the stromal CD34 expression should be handled with care when used as a diagnostic tool.

Beyond mere markers: functions for CD34 family of sialomucins in hematopoiesis

CD34, podocalyxin, and endoglycan are members of a family of single-pass transmembrane proteins that show distinct expression on early hematopoietic precursors and vascular-associated tissue. In spite of the fact that the expression of CD34 on these early progenitors has been known for over 20 yr and used clinically in hematopoietic stem cell transplantation for more than 15 yr, little is known about its exact role or function. More recently, CD34 expression has been shown to distinguish activated early progenitors from quiescent cells. With the subsequent identification of podocalyxin and endoglycan as related family members also expressed on early progenitor cells, attention is slowly shifting toward understanding how these molecules might contribute to progenitor function and behavior. In this review we examine the existing evidence and propose testable models to reveal the importance of these molecules for stem and progenitor cell function.

Beyond mere markers: functions for CD34 family of sialomucins in hematopoiesis

CD34, podocalyxin, and endoglycan are members of a family of single-pass transmembrane proteins that show distinct expression on early hematopoietic precursors and vascular-associated tissue. In spite of the fact that the expression of CD34 on these early progenitors has been known for over 20 yr and used clinically in hematopoietic stem cell transplantation for more than 15 yr, little is known about its exact role or function. More recently, CD34 expression has been shown to distinguish activated early progenitors from quiescent cells. With the subsequent identification of podocalyxin and endoglycan as related family members also expressed on early progenitor cells, attention is slowly shifting toward understanding how these molecules might contribute to progenitor function and behavior. In this review we examine the existing evidence and propose testable models to reveal the importance of these molecules for stem and progenitor cell function.

CD34+ fibrocytes in normal mitral valves and myxomatous mitral valve degeneration

We investigated a total of 15 mitral valves with myxomatous degeneration and compared these with normal mitral valves. In normal mitral valves, stromal cells located in the fibrosa and spongiosa showed small bipolar cytoplasmic processes and were found to be positive for CD34, suggesting a close relationship to CD34+ fibrocytes. In cases of myxomatous degeneration, stromal cells showed an altered morphology in that they exhibited multipolar cytoplasmic processes, appeared to be hyperplastic, and were increased in number. This study is the first to report on CD34+ fibrocytes making up the majority of mitral valve stromal cells. Major factors in the development of myxomatous valve degeneration are MMP-9, as well as collagen I and III, which have been reported to be secreted by CD34+ fibrocytes. Therefore, it is likely that CD34+ fibrocytes are involved in the pathogenesis of myxomatous mitral valve degeneration.

Comparative study of CD34, alpha-SMA and h-caldesmon expression in the stroma of gynaecomastia and male breast carcinoma

AIMS

To address the fibroblastic/myofibroblastic nature of stroma in gynaecomastia and in male breast carcinoma, the expression of CD34, alpha-smooth muscle actin (SMA) and h-caldesmon in the stromal cells was investigated by immunohistochemistry.

METHODS AND RESULTS

Representative archival paraffin blocks were collected from male patients with gynaecomastia (32 cases) and mammary carcinoma (24 cases) between 1984 and 2004 and CD34, alpha-SMA and h-caldesmon were assessed immunohistochemically using a streptavidin-biotin method. Thirty cases of gynaecomastia showed a CD34+, alpha-SMA- and h-caldesmon- immunophenotype with different CD34 staining intensity in the various histological subtypes. Positivity for alpha-SMA and negativity for CD34 and h-caldesmon was found in a case of florid gynaecomastia relating to reactive fibrosis due to previous surgical intervention. Acquisition of alpha-SMA expression by stromal fibroblasts but absence of CD34 staining was identified in 22 cases of male breast carcinoma.

CONCLUSIONS

The immunophenotype of periductal connective tissue stroma in gynaecomastia appears to parallel the phenotype of normal breast stroma. In male breast carcinoma the stromal cell immunophenotype is similar to that of its female counterpart showing myofibroblastic differentiation. However alpha-SMA+ and CD34- are not specific to malignancy because such findings are also encountered in reactive fibrosis.

Stromal remodeling and SPARC (secreted protein acid rich in cysteine) expression in invasive ductal carcinomas of the breast

In the present study, we analyzed tumor associated stromal remodeling with special respect to SPARC (secreted protein acid rich in cysteine) expression. 25 invasive ductal carcinomas of the breast and corresponding tumor-free breast tissue were studied immunohistochemically (CD34, alpha-SMA, SPARC and TGFbeta-R1). Tumor associated stroma was characterized by a loss of CD34 expression, paralleled by a gain in alpha-SMA. While SPARC expression was virtually absent from normal stromal cells in the tumor stroma, strong cytoplasmic SPARC reactivity was found in the majority of stromal cells. The TGFbeta-R1 also showed stronger expression in the tumor stroma compared to that of the normal breast. Stromal response to antecedent core needle biopsy was similar to that observed in the tumor stroma. We conclude that SPARC overexpression is a constant and functionally important feature of invasive ductal carcinomas, since SPARC mediates stromal de-adhesion crucial for local tumor invasion and systemic spread, respectively. When considering changes of the stromal phenotype (normal: CD34+alpha-SMA-SPARC- vs. carcinoma: CD34-alpha-SMA+SPARC+) as a tool in distinguishing benign from malignant breast lesion one has to keep in mind that the phenotype of granulation tissue in areas of antecedent biopsy resembles that of tumor stroma.

Expression of CD34, alpha-smooth muscle actin, and transforming growth factor beta1 in squamous intraepithelial lesions and squamous cell carcinoma of the larynx and hypopharynx

AIM OF THE STUDY

There is increasing evidence that stromal reaction in cancer has an important diagnostic and prognostic significance. Recent studies have shown that CD34-positive stromal cells and myofibroblasts may play an important role in host response to invasive cancer. The aim of our study was to analyze the expression of CD34, alpha-smooth muscle actin (SMA), and transforming growth factor beta1 (TGFbeta1) in squamous intraepithelial lesions (SILs) and squamous cell carcinoma (SCC) of the larynx and hypopharynx, to establish their significance, and to elucidate the mechanism of myofibroblast formation.

METHODS

Immunohistochemistry was performed on samples of 42 resected larynges and 12 laryngeal biopsies of SILs and SCC using antibodies against SMA, CD34, CD31, TGFbeta1, and TGFbeta1 receptors. The expression of TGFbeta1 mRNA was detected with RNA in situ hybridization using specific oligonucleotides for TGFbeta1.

RESULTS

The stroma in normal laryngeal mucosa and SILs contained scattered CD34-positive cells, but there were no SMA-positive myofibroblasts. In contrast, the stroma of SCC contained SMA-positive myofibroblasts, but there were no CD34-positive stromal cells. This pattern of stromal reaction was also observed in the peritumoral zone. In adjacent normal tissue, there were CD34-positive stromal cells and no myofibroblasts. We found more intense TGFbeta1 expression in carcinoma cells than in the normal laryngeal epithelium and positive staining for both TGFbeta1 receptors on stromal cells of the normal mucosa. In SCC, many myofibroblasts expressed TGFbeta1 and both receptors for TGFbeta1. Expression of TGFbeta1 mRNA was similar to expression of TGFbeta1 protein.

CONCLUSION

Our study shows that disappearance of CD34-positive stromal cells and appearance of SMA-positive stromal myofibroblasts are associated with transformation of laryngeal SILs to SCC. This pattern of stromal reaction was found not only in the tumor but also in the peritumoral zone, defined as a band of host tissue between the invasive tumor front and adjacent normal tissue. Our findings also support the suggestion that overproduced TGFbeta1 in carcinoma cells mediates one of the mechanisms of transformation of stromal cells to myofibroblasts in laryngeal carcinogenesis.

Bone marrow contribution to tumor-associated myofibroblasts and fibroblasts

The role of myofibroblasts in tissue repair and fibrosis is well documented, but the source of these myofibroblasts is unclear. There is evidence of a circulating population of fibrocytes that can home to areas of injury and contribute to myofibroblast populations. Previously, we have shown that the bone marrow is a source of myofibroblasts for many tissues including the gut, lung, and kidney and that this phenomenon is exacerbated by injury. We now show that the bone marrow can contribute to myofibroblast and fibroblast populations in tumor stroma in a mouse model of pancreatic insulinoma. Mice transgenic for the rat insulin promoter II gene linked to the large-T antigen of SV40 (RIPTag) develop solid beta-cell tumors of the pancreas. Approximately 25% of myofibroblasts in these pancreatic tumors were donor-derived, and these were concentrated toward the edge of the tumor. Thus, the development of tumor stroma is at least in part a systemic response that may ultimately yield methods of targeting new therapy.

The potential value of (Myo)fibroblastic stromal reaction in the diagnosis of prostatic adenocarcinoma

BACKGROUND

Reactive stromal changes that occur in different human cancers probably are involved in local tumor spreading. The aim of this study was to analyze changes of the stroma in prostatic carcinoma and to establish their possible diagnostic significance.

METHODS

For the definition of reactive stroma in prostate cancer Mallory trichrome method and immunohistochemical analysis of vimentin, alpha-smooth muscle actin, and desmin were performed.

RESULTS

Compared with adjacent peritumoral tissue and stroma in benign prostatic hyperplasia, reactive stroma in prostate cancer showed increased vimentin expression, and decreased desmin expression (P < 0.05). Mallory method also showed more pronounced desmoplastic reaction in stroma of prostatic adenocarcinoma (P < 0.05).

CONCLUSIONS

Our study indicates that a reactive stroma, which occurs in prostatic carcinoma, could be clearly shown by Mallory method and confirmed by immunohistochemistry. We suggest that Mallory trichrome method may be used as a helpful additional diagnostic tool in the diagnosis of suspicious cases of prostatic adenocarcinoma.

Application of a clinical grade CD34-mediated method for the enrichment of microvascular endothelial cells from fat tissue

BACKGROUND

Microvascular endothelial cells (MVEC) derived from s.c. fat are seeded on vascular grafts to prevent early occlusion. We have demonstrated the presence of contaminating cells contributing to MVEC seeding-related intimal hyperplasia in MVEC isolates from fat tissue. We found that cell isolates additionally purified after the isolation process, were associated with a reduced thrombogenicity and development of intimal hyperplasia in vitro. A combination of 11Fibrau (F11)- and CD14-coated Dynabeads was used to deplete the contaminating cells, fibroblasts, and monocytes/macrophages. Unfortunately, clinical-grade F11 is not available, and thus cannot be used for clinical practice. CD34 selection with clinical-grade products is widely used for the isolation of hematopoietic progenitors, and endothelial cells (EC) express CD34 on their surfaces. The aims of this study were to test the effectiveness of two different CD34-selection techniques for purification of MVEC, and to compare the results with those of the F11/CD14-method.

METHODS

Liposuction fat was enzymatically digested and centrifuged twice to remove adipocytes and collagenase. CD34 selection was performed using the commercially available methods from Nexell or Miltenyi. Both techniques were modified for our use. The purity after isolation and culture, and recovery were determined by flow-cytometry (CD31-expression) and compared with that of cells purified with the F11/CD14-method.

RESULTS

Besides MVEC, the contaminating fibroblasts and macrophages/monocytes weakly expressed the CD34 Ag. Enrichment of MVEC was not successful with the Miltenyi method. Variations in neither the dose of Ab nor the use of direct selection and different separation programs improved the results. With the Nexell method, MVEC were enriched to 86%, a comparable purity to that obtained with the F11/CD14-method. However, a lower recovery was achieved with the Nexell method.

CONCLUSION

Enrichment of MVEC could be achieved with a modified protocol of the clinical grade CD34(+) selection method from Nexell, but not with the CD34 method from Miltenyi.

Clinicopathological significance of stromal myofibroblasts in invasive ductal carcinoma of the breast

The purpose of this study was to investigate the distribution of CD34-positive fibroblasts and alpha-smooth muscle actin (alpha-SMA)-reactive myofibroblasts in the stroma of benign and malignant breast lesions and, secondly, to determine whether the presence of stromal myofibroblasts is associated with some of the clinicopathological characteristics of patients with invasive ductal carcinoma. The presence of stromal CD34-positive fibroblasts and myofibroblasts was investigated (as defined immunohistochemically) in 8 normal breast tissue samples, 58 invasive ductal carcinomas, 9 ductal carcinomas in situ and 16 specimens with benign lesions of the breast (fibroadenomas, ductal hyperplasias). We further studied the correlations between the presence of stromal myofibroblasts with 7 clinicopathological parameters in 58 invasive ductal carcinomas. The results indicated that the stroma of normal breast tissues contained CD34-positive fibroblasts. All benign breast lesions exhibited stromal CD34-positive fibroblasts. In contrast, the stroma of ductal carcinomas showed a complete loss of CD34-positive fibroblasts. alpha-SMA expression in stromal fibroblasts (myofibroblasts) was not detected in normal tissue samples or benign lesions except in 1 case of fibroadenoma, whereas positive myofibroblasts were found in 44.4% of ductal carcinomas in situ and 56.9% of invasive breast carcinomas. Comparison of clinicopathological parameters between invasive ductal carcinomas with and without stromal myofibroblasts revealed significant differences in lymph node metastasis, high histological grade and high microvessel density. These results suggest that CD34 loss and the presence of myofibroblasts favor the diagnosis of breast carcinoma. In invasive ductal carcinoma, the presence of stromal myofibroblasts correlated significantly with pathological parameters associated with a poor prognosis.

COX-2+ myofibroblasts may play a key role in marked stromal fibrosis in strictured colorectal carcinomas

AIMS

To elucidate the mechanism of marked stromal fibrosis in strictured colorectal carcinomas (SC) that cause complete ileus.

METHODS AND RESULTS

Sixteen cases of SC and 29 cases of non-strictured colorectal carcinoma (NSC) were studied. These carcinomas showed similar clinicopathological features except for bowel stricture. The stricture index (SI) showing the degree of bowel stricture was 59.8 +/- 12.1% in SC versus 20.8 +/- 24.6% in NSC (P < 0.001). The fibrosis index (FI), defined to reflect the extent of stromal fibrosis, was 56.3 +/- 8.8% in SC versus 21.9 +/- 10.6% in NSC (P < 0.001). COX-2+ myofibroblasts were detected in 13 cases (81.3%) in SC versus eight cases (27.6%) in NSC (P < 0.01). The COX-2+ myofibroblast density was 276.7 +/- 181.1 cells/mm(2) in SC versus 26.6 +/- 52.7 cells/mm(2) in NSC (P < 0.001). When all cases were divided into two groups with and without COX-2+ myofibroblasts, the SI was 48.8 +/- 19.1% in those with COX-2+ myofibroblasts versus 24.8 +/- 29.3% in those with COX-2- myofibroblasts (P < 0.001).

CONCLUSION

COX-2+ myofibroblasts may play an important role in extensive bowel stricture in colorectal carcinomas.

CD34+ fibrocytes, alpha-smooth muscle antigen-positive myofibroblasts, and CD117 expression in the stroma of invasive squamous cell carcinomas of the oral cavity, pharynx, and larynx

We investigated tumor-free mucosa and squamous cell carcinomas of the oral cavity, the pharynx, and larynx with respect to the presence of stromal CD34+ fibrocytes and alpha-smooth muscle antigen (SMA)-positive myofibroblasts. Additionally, stromal expression of CD117 was analyzed. A total of 39 squamous cell carcinomas were assessed immunohistochemically. In all cases investigated, CD34+ fibrocytes were found in the tumor-free stroma, whereas alpha-SMA-positive myofibroblasts were lacking. Areas of lymphocytic infiltration disclosed a focal reduction of CD34+ fibrocytes. CD117 expression was absent from the tumor-free stroma. Of 39 squamous cell carcinomas, 33 were free of stromal CD34+ fibrocytes, and, in 31 carcinomas, stromal alpha-SMA-positive myofibroblasts occurred at least focally. CD117-positive stromal spindle cells were found in 25 carcinomas. Compared with tumor-free mucosa, the number of tissue mast cells was significantly increased in carcinomas. We conclude that stromal remodeling induced by invasive carcinomas is characterized by a loss of CD34+ fibrocytes and subsequent gain of alpha-SMA-positive myofibroblasts. The diagnostic impact of this finding is, however, limited by the fact that chronic inflammation may also be accompanied by a focal loss of CD34+ fibrocytes.

Immunohistochemical characterization of fibroblast subpopulations in normal peritoneal tissue and in peritoneal dialysis-induced fibrosis

Peritoneal fibrosis is one of the most common morphological changes observed in continuous ambulatory peritoneal dialysis (CAPD) patients. Both resident fibroblasts and new fibroblast-like cells derived from the mesothelium by epithelial-to-mesenchymal transition are the main cells involved fibrogenesis. In order to establish markers of peritoneal impairment and pathogenic clues to explain the fibrogenic process, we conducted an immunohistochemical study focused on peritoneal fibroblasts. Parietal peritoneal biopsies were collected from four patient groups: normal controls ( n = 15), non-CAPD uremic patients ( n = 17), uremic patients on CAPD ( n = 27) and non-renal patients with inguinal hernia ( n = 12). To study myofibroblastic conversion of mesothelial cells, alpha-smooth muscle actin (SMA), desmin, cytokeratins and E-cadherin were analyzed. The expression of CD34 by fibroblasts was also analyzed. Fibroblasts from controls and non-CAPD uremic patients showed expression of CD34, but no myofibroblastic or mesothelial markers. The opposite pattern was present during CAPD-related fibrosis. Expression of cytokeratins and E-cadherin by fibroblast-like cells and alpha-SMA by mesothelial and stromal cells supports that mesothelial-to-myofibroblast transition occurs during CAPD. Loss of CD34 expression correlated with the degree of peritoneal fibrosis. The immunophenotype of fibroblasts varies during the progression of fibrosis. Myofibroblasts seem to derive from both activation of resident fibroblasts and local conversion of mesothelial cells.

Are CD34+ cells found in renal interstitial fibrosis?

BACKGROUND

The CD34 antigen is a marker of precursor myeloid cells and endothelial cells, but also of a subset of spindle cells.

METHODS

To establish the possible role of CD34+ cells in the progression of glomerulonephritis, 30 renal biopsies were investigated. Immunohistochemistry for CD34 and smooth muscle actin (SMA) were performed by standard methods. The results were assessed semiquantitatively. The relative interstitial volume (RIV) was evaluated by the point counting method. Clinical data such as sex, age, serum creatinine and urea levels were taken into account.

RESULTS

CD34+ spindle cells and SMA+ myofibroblasts were present in the renal interstitium in all but one case. In membranous, membranoproliferative and segmental-proliferative glomerulonephritis, CD34+ cells were seen in clusters, while in IgA nephropathy and in segmental and focal glomerulosclerosis, single, scattered cells were seen. The density of CD34+ cells showed a positive correlation with the myofibroblast density and the RIV. Serum creatinine and urea levels were associated with the RIV of the kidney and to a smaller degree with the number of myofibroblasts and CD34+ cells.

CONCLUSION

These results show that in glomerulonephritis, CD34+ spindle cells appear in the interstitium. At present, their possible role can only be speculated.

CD34+ fibrocytes in tubular carcinomas and radial scars of the breast

The present study was undertaken to analyze whether and to what extent CD34+ fibrocytes and alpha-smooth muscle actin (alpha-SMA)-positive myofibroblasts occur in the stroma of radial scars and tubular carcinoma of the breast. We investigated a total of 24 radial scars obtained from 23 females and a total of 43 tubular carcinomas. All tubular carcinomas showed a virtually complete loss of CD34+ fibrocytes paralleled by a gain of alpha-SMA-positive myofibroblasts. The peripheral parts of radial scars harbored CD34+ fibrocytes comparable to normal breast tissue. In 23 of 24 radial scars, the central core was characterized by a loss of CD34+ fibrocytes accompanied by the presence of alpha-SMA-positive myofibroblasts in six cases, a pattern that up to now has only been described in malignant breast lesions. This finding underlines the close relationship between tubular carcinomas and radial scars. We conclude CD34- and alpha-SMA immunohistochemistry to be valuable adjunctive tools in distinguishing radial scars from tubular carcinomas. In the present study, the presence of CD34+ fibrocytes excluded malignancy. The absence of CD34+ fibrocytes paralleled by the presence of alpha-SMA myofibroblasts indicated malignancy in most cases, although it has to be carefully considered that in a minority of cases (6 of 24) the central core of radial scars may disclose this stromal composition.