Glypican-3 and Hep Par-1 are Useful Biomarkers in the Cytologic Assessment of Ascites.

Till date, the utility of cytologic assessment of ascites for the identification of hepatocellular carcinoma (HCC) cells is still debated and the usefulness of immunocytochemistry for glypican-3 (GPC3) and Hep Par-1 in this setting has not been reported. Liquid-based cytology of ascitic fluid of 28 cirrhotic patients was performed and the spots obtained were stained with hematoxylin and eosin, papanicolau, and with GPC3 and Hep Par-1 antibodies. GPC3 and Hep Par-1 antibodies stained positively the atypical cells in the ascites of 2 patients with HCC showing an exophytic growth pattern. The specimens of the patients with nonexophytic HCC, other non-HCC cancers, or cirrhosis stained negatively. We hypothesize a relationship with the exophytic growth of the tumor. Thus, GPC3 and Hep Par-1 are useful in the cytologic assessment of peritoneal effusions to distinguish mesothelial cells and neoplastic non-HCC cells from HCC cells, presence of which, however, represent a very rare event. This is the first study in which GPC3 and Hep Par-1 immunostaining has been used in the cytologic assessment of HCC ascites.

Pleural epithelioid angiosarcoma with lymphatic differentiation arisen after radiometabolic therapy for thyroid carcinoma: immunohistochemical findings and review of the literature.

BACKGROUND: Pleural angiosarcoma is a rare tumor that causes diffuse pleural thickening and effusion, mimicking mesothelioma. Immunohistochemistry is needed to highlight endothelial differentiation. We describe the first case of pleural angiosarcoma with lymphatic differentiation following radiometabolic therapy for thyroid carcinoma. CASE PRESENTATION: A 50-year-old man showed diffuse pleural thickening and effusion. Nine years earlier, he underwent thyroidectomy and radiometabolic therapy for thyroid carcinoma with lymph node metastases. Histologically, the tumor consisted of a solid proliferation of atypical epithelioid cells and anastomosed vascular spaces, lacking of red blood cells and containing Alcian blue positive material. The tumor showed positive immunostaining for Vimentin, CD31, CK7, D2-40, c-MYC, Ki67, focal positivity for PanCK, and negative immunostaining for Factor VIII, CD34, WT1, CK5/6, Calretinin, EMA, HBME-1, CEA, p63, EpCAM, Bcl-2, TTF1 and Thyroglobulin. CD99 showed a granular/paranuclear pattern of positivity. The histological and immunohistochemical features were consistent with "pleural angiosarcoma with lymphatic differentiation, epithelioid variant". DISCUSSION AND CONCLUSIONS: Epithelioid angiosarcoma with lymphatic differentiation is very rare and aggressive. Moreover, the positivity for c-MYC suggests the relationship with radiometabolic therapy. To our knowledge, this is the first case of pleural c-MYC-positive angiosarcoma with lymphatic differentiation reported in the literature and the first one arisen after radiometabolic therapy for thyroid carcinoma.

Mast cells contribute to autoimmune diabetes by releasing interleukin-6 and failing to acquire a tolerogenic IL-10+ phenotype.

Mast cells (MCs) are innate immune cells that exert positive and negative immune modulatory functions capable to enhance or limit the intensity and/or duration of adaptive immune responses. Although MCs are crucial to regulate T cell immunity, their action in the pathogenesis of autoimmune diseases is still debated. Here we demonstrate that MCs play a crucial role in T1D pathogenesis so that their selective depletion in conditional MC knockout NOD mice protects them from the disease. MCs of diabetic NOD mice are overly inflammatory and secrete large amounts of IL-6 that favors differentiation of IL-17-secreting T cells at the site of autoimmunity. Moreover, while MCs of control mice acquire an IL-10+ phenotype upon interaction with FoxP3+ Treg cells, MCs of NOD mice do not undergo this tolerogenic differentiation. Our data indicate that overly inflammatory MCs unable to acquire a tolerogenic IL-10+ phenotype contribute to the pathogenesis of autoimmune T1D.

Analysis of tissue and circulating microRNA expression during metaplastic transformation of the esophagus.

Genetic changes involved in the metaplastic progression from squamous esophageal mucosa toward Barrett's metaplasia and adenocarcinoma are almost unknown. Several evidences suggest that some miRNAs are differentially expressed in Barrett's esophagus (BE) and esophageal adenocarcinoma. Among these, miR-143, miR-145, miR-194, miR-203, miR-205, miR-215 appear to have a key role in metaplasia and neoplastic progression. The aim of this study was to analyze deregulated miRNAs in serum and esophageal mucosal tissue biopsies to identify new biomarkers that could be associated with different stages of esophageal disease. Esophageal mucosal tissue biopsies and blood samples were collected and analyzed for BE diagnosis. Quantitative Real-time PCR was used to compare miRNA expression levels in serum and 60 disease/normal-paired tissues from 30 patients diagnosed with esophagitis, columnar-lined esophagus (CLO) or BE. MiRNA expression analysis showed that miR-143, miR-145, miR-194 and miR-215 levels were significantly higher, while miR-203 and miR-205 were lower in BE tissues compared with their corresponding normal tissues. Esophageal mucosa analysis of patients with CLO and esophagitis showed that these miRNAs were similarly deregulated but to a lesser extent keeping the same trend and CLO appeared as intermediate step between esophagitis and BE. Analysis on circulating miRNA levels confirmed that miR-194 and miR-215 were significantly upregulated in both BE and CLO compared to esophagitis, while miR-143 was significantly upregulated only in the Barrett group. These findings suggest that miRNAs may be involved in neoplastic/metaplastic progression and miRNA analysis might be useful for progression risk prediction as well as for monitoring of BE/CLO patients.

CD1A-positive cells and HSP60 (HSPD1) levels in keratoacanthoma and squamous cell carcinoma.

CD1a is involved in presentation to the immune system of lipid antigen derived from tumor cells with subsequent T cell activation. Hsp60 is a molecular chaperone implicated in carcinogenesis by, for instance, modulating the immune reaction against the tumor. We have previously postulated a synergism between CD1a and Hsp60 as a key factor in the activation of an effective antitumor immune response in squamous epithelia. Keratoacantomas (KAs) are benign tumors that however can transform into squamous cell carcinomas (SCCs), but the reasons for this malignization are unknown. In a previous study, we found that CD1a-positive cells are significantly more numerous in KA than in SCC. In this study, we analyzed a series of KAs and SCCs by immunohistochemistry for CD1a and Hsp60. Our results show that the levels of both are significantly lower in KA than in SCC and support the hypothesis that KA may evolve towards SCC if there is a failure of the local modulation of the antitumor immune response. The data also show that immunohistochemistry for CD1a and Hsp60 can be of help in differential diagnosis between KAs and well-differentiated forms of SCC.

Comparison of Histochemical Stainings in Evaluation of Liver Fibrosis and Correlation with Transient Elastography in Chronic Hepatitis.

Background and Aim. The best staining to evaluate liver fibrosis in liver hepatitis is still a debated topic. This study aimed to compare Masson's trichrome (MT), Sirius Red (SR), and orcein stainings in evaluating liver fibrosis in chronic HCV hepatitis (CHC) with semiquantitative and quantitative methods (Collagen Proportionate Area (CPA) by Digital Image Analysis (DIA)) and correlate them with transient elastography (TE). Methods. Liver stiffness evaluation of 111 consecutive patients with CHC was performed by TE. Semiquantitative staging by Metavir score system and CPA by DIA were assessed on liver biopsy stained with MT, SR, and orcein. Results. MT, SR, and orcein staining showed concordant results in 89.6% of cases in staging CHC, without significant difference in both semiquantitative and quantitative evaluations of fibrosis. TE values were concordant with orcein levels in 86.5% of the cases and with MT/RS in 77.5% (P < 0.001). No significant correlation between the grade of necroinflammatory activity and TE values was found. Conclusion. In CHC, SR/MT and orcein stainings are almost concordant and when discordant, orcein staining is better related to TE values than MT/RS. This suggests that elastic fibers play a more important role than reticular or collagenous ones in determining stiffness values in CHC.

Nodular histiocytic/mesothelial hyperplasia as consequence of chronic mesothelium irritation by subphrenic abscess.

PURPOSE: Pleural nodular histiocytic/mesothelial hyperplasia is a nodular histiocytic/mesothelial proliferation, often delimiting cystic cavities, due to irritation by a pulmonary noxa. Case report results: The patient had right pleural parietal and diaphragmatic thickness, with pleural effusion, without lung alterations. He previously underwent left hemicolectomy and liver resection, due to a diverticulitis and a liver histiocytes-rich abscess. Video-assisted thoracoscopy biopsy showed a double population of reactive mesothelial cells and histiocytes. CONCLUSION: Nodular histiocytic/mesothelial hyperplasia represents a potential pitfall for pathologists. Immunohistochemistry is crucial for the differential diagnosis with some malignancies. We suggest that in our patient, a chronic mesothelium inflammation happened by transdiaphragmatic involvement as a consequence of the liver abscess. Some pathogenetic mechanisms are hypothesized.

Comparison of Histochemical Staining Methods and Correlation with Transient Elastography in Acute Hepatitis.

OBJECTIVE: To compare Masson's trichrome (MT), Sirius red (SR) and orcein staining in acute hepatitis (AH) and to correlate them with transient elastography (TE), a noninvasive method to assess hepatic fibrosis. METHODS: We evaluated liver stiffness by TE in a cohort of 34 consecutive patients and assessed MT-, SR- and orcein-stained biopsies using the METAVIR scoring system and digital image analysis (DIA). RESULTS: MT and SR both showed severe fibrosis (stage III-IV, DIA = 12.7%). Orcein showed absent or mild fibrosis (stage 0-II, DIA = 4.4%; p < 0.05). In 29/34 cases (85%), stiffness values were >12.5 kPa, in keeping with SR/MT but not with orcein results. CONCLUSIONS: Even though in AH true elastic fibrosis is typically absent or mild, TE shows elevated stiffness values, in keeping with SR/MT evaluations. If not properly evaluated in the clinical context, these results would lead to an overestimation of fibrosis. Orcein is the only staining able to evidence the absence of true elastic fibrosis, which is a typical feature of AH. This is the first study comparing different staining procedures performed on AH biopsies by DIA versus TE. © 2015 S. Karger AG, Basel.

Class IIa HDACs repressive activities on MEF2-depedent transcription are associated with poor prognosis of ER⁺ breast tumors.

MEF2s transcription factors and class IIa HDACs compose a fundamental axis for several differentiation pathways. Functional relationships between this axis and cancer are largely unexplored. We have found that class IIa HDACs are heterogeneously expressed and display redundant activities in breast cancer cells. Applying gene set enrichment analysis to compare the expression profile of a list of putative MEF2 target genes, we have discovered a correlation between the down-regulation of the MEF2 signature and the aggressiveness of ER(+) breast tumors. Kaplan-Meier analysis in ER(+) breast tumors evidenced an association between increased class IIa HDACs expression and reduced survival. The important role of the MEF2-HDAC axis in ER(+) breast cancer was confirmed in cultured cells. MCF7 ER(+) cells were susceptible to silencing of class IIa HDACs in terms of both MEF2-dependent transcription and apoptosis. Conversely, in ER(-) MDA-MB-231 cells, the repressive influence of class IIa HDACs was dispensable. Similarly, a class IIa HDAC-specific inhibitor preferentially promoted the up-regulation of several MEF2 target genes and apoptosis in ER(+) cell lines. The prosurvival function of class IIa HDACs could be explained by the repression of NR4A1/Nur77, a proapoptotic MEF2 target. In summary, our studies underscore a contribution of class IIa HDACs to aggressiveness of ER(+) tumors.-Clocchiatti, A., Di Giorgio, E., Ingrao, S., Meyer-Almes, F.-J., Tripodo, C., Brancolini, C. Class IIa HDACs repressive activities on MEF2-depedent transcription are associated with poor prognosis of ER(+) breast tumors.

High liver RBP4 protein content is associated with histological features in patients with genotype 1 chronic hepatitis C and with nonalcoholic steatohepatitis.

BACKGROUND AND AIM: To investigate the hepatic expression of retinol-binding protein-4 (RBP4) in chronic hepatitis C (CHC) and nonalcoholic steatohepatitis (NASH) patients, and its association with biochemical and histological patterns of liver damage. MATERIALS AND METHODS: Sixty-six genotype 1 CHC and 32 NASH patients were tested for hepatic RBP4 expression. Liver expression at immunostaining was scored as 0 (slight), 1 (mild), 2 (moderate), and 3 (intense). In addition, the mRNA and the quantitative protein expressions of RBP4 were tested by PCR and by western blot, respectively, in 12 NASH and 28 CHC patients. Twelve subjects undergoing elective cholecystectomy served as controls. RESULTS: Ten (31%), 16 (50%) and 6 (19%) NASH patients, and 21 (32%), 31 (47%) and 14 (21%) CHC patients had scores of 1, 2 and 3, respectively. All control subjects scored 0. In both CHC and NASH liver RBP4 scores were directly related to western blot (p=0.001 and p=0.03), not to mRNA expression (p=0.77 and p=0.40). Older age (OR, 1.07; 95%CI, 1.01-1.13), RBP4 score (4.26; 1.27-14.21) and HOMA (2.26; 1.15-4.42) were independently associated with steatosis≥10% in CHC patients. In NASH lobular inflammation (OR, 3.77; 95%CI, 1.01-24.22) and RBP4 score (4.87; 1.003-23.65) were the only risk factors for fibrosis ≥2 at logistic regression analysis. CONCLUSION: Hepatic storage of RBP4, unrelated to its expression, could cause liver damage both in NASH and CHC.

Metastatic seeding of colon adenocarcinoma manifesting as synchronous breast and chest wall localization: report of a case.

Colon carcinoma rarely metastasizes to the breast and it is usually associated with a poor prognosis. Even rarer is metastatic seeding of colon cancer cells in an intramammary location after surgery. Including a primary breast malignancy in the differential diagnosis of such cases is mandatory. We report a rare case of double seeding implantation of colon adenocarcinoma inside the breast parenchyma and intercostal muscles 6 years after resection of a pulmonary metastasis from colon adenocarcinoma. The metastasis was revealed by the presence of bone metaplasia in the intercostal muscles. We discuss how negative immunostaining for estrogen receptors, progesterone receptors, and HER-2, along with the immunohistochemical pattern of cytokeratin (CK) 20+/7-/5- and CDX2-positive immunostaining, excludes a primary breast malignancy, namely, a "matrix-producing" carcinoma, from the differential diagnosis. We also present the hypothesis of a paracrine pathogenetic mechanism to explain the bone metaplasia.

Exploratory study on the effects of biodegradable nanoparticles with drugs on malignant B cells and on a human/mouse model of Burkitt lymphoma.

The aim of this study was to determine if Rituximab coated Biodegradable Nanoparticles (BNPs) loaded with Chlorambucil and Hydroxychloroquine could induce apoptosis of B-Chronic Lymphocytic Leukemia (B-CLL), MEC-1 and BJAB cells in vitro and evaluate their toxic and therapeutic effects on a Human/Mouse Model of Burkitt Lymphoma at an exploratory, proof of concept scale. We found that Rituximab-Chlorambucil-Hydroxychloroquine BNPs induce a decrease in cell viability of malignant B cells in a dose-dependent manner. The mediated cytotoxicity resulted from apoptosis, and was confirmed by monitoring the B-CLL cells after Annexin V/propidium iodide staining. Additional data revealed that these BNPs were non toxic for healthy animals, and had prolonged survival in this mice model of human lymphoma.

Human bone marrow mesenchymal stem cells display anti-cancer activity in SCID mice bearing disseminated non-Hodgkin's lymphoma xenografts.

BACKGROUND: Although multimodality treatment can induce high rate of remission in many subtypes of non-Hodgkin's lymphoma (NHL), significant proportions of patients relapse with incurable disease. The effect of human bone marrow (BM) mesenchymal stem cells (MSC) on tumor cell growth is controversial, and no specific information is available on the effect of BM-MSC on NHL. METHODOLOGY/PRINCIPAL FINDINGS: The effect of BM-MSC was analyzed in two in vivo models of disseminated non-Hodgkin's lymphomas with an indolent (EBV(-) Burkitt-type BJAB, median survival = 46 days) and an aggressive (EBV(+) B lymphoblastoid SKW6.4, median survival = 27 days) behavior in nude-SCID mice. Intra-peritoneal (i.p.) injection of MSC (4 days after i.p. injection of lymphoma cells) significantly increased the overall survival at an optimal MSC:lymphoma ratio of 1:10 in both xenograft models (BJAB+MSC, median survival = 58.5 days; SKW6.4+MSC, median survival = 40 days). Upon MSC injection, i.p. tumor masses developed more slowly and, at the histopathological observation, exhibited a massive stromal infiltration coupled to extensive intra-tumor necrosis. In in vitro experiments, we found that: i) MSC/lymphoma co-cultures modestly affected lymphoma cell survival and were characterized by increased release of pro-angiogenic cytokines with respect to the MSC, or lymphoma, cultures; ii) MSC induce the migration of endothelial cells in transwell assays, but promoted endothelial cell apoptosis in direct MSC/endothelial cell co-cultures. CONCLUSIONS/SIGNIFICANCE: Our data demonstrate that BM-MSC exhibit anti-lymphoma activity in two distinct xenograft SCID mouse models of disseminated NHL.

Cyclooxygenase-2 expression in chronic liver diseases and hepatocellular carcinoma: an immunohistochemical study .

UNLABELLED: Hepatocarcinogenesis is a multistep process characterized by hepatocyte inflammation, regeneration, and proliferation. These changes are believed to depend on the aberrant expression of various tumor suppressor genes, oncogenes and growth factors. Several studies have shown the involvement of cyclooxygenase-2 (COX-2), the inducible isoform of the enzymes that catalyze prostaglandin synthesis in various aspects of carcinogenesis. COX-2 has been described as being overexpressed in hepatocellular carcinoma (HCC) patients. Using immunohistochemistry, we studied COX-2 expression in different chronic liver diseases (CLD) including nonalcoholic steatohepatitis (NASH), chronic hepatitis (CH), liver cirrhosis (LC), and HCC in a population referred to a tertiary center in western Sicily, an area moderately endemic for CLD. Sixteen NASH, 35 CH, 15 LC, and 21 HCC samples were analyzed. Positive signs of COX-2 were observed in the cytoplasm of hepatocytes and median values were 6 (3-9) for NASH, 7 (3-9) for CH, 6 (4-9) for LC, and 4 (0-7) for HCC. COX-2 expression was significantly lower in HCC than in NASH (P < 0.001), CH (P < 0.0001), and LC (P < 0.0001). In HCC we found a wide range of COX-2 expression: from no expression in poorly differentiated areas to a high expression in well-differentiated ones, with an inverse correlation between COX-2 and tumor grading, according to Edmonson (rho=-0.67, P < 0.0001). IN CONCLUSION: (a) COX-2 expression was significantly lower in HCC than in the other CLD; (b) COX-2 expression inversely correlated with tumor differentiation status. These results suggest that COX-2 expression could be related to the inflammatory phenomena present in the early phases of CLD and eventually to the induction of hepatocarcinogenesis.

CD146(+) bone marrow osteoprogenitors increase in the advanced stages of primary myelofibrosis.

CD146(+) bone marrow stromal cells have been recently recognized as clonogenic osteoprogenitors able to organize a complete hematopoietic microenvironment. In this study we used immunohistochemical analysis to investigate the contribution of CD146(+) bone marrow osteoprogenitors to the stromal remodeling occurring in the different stages of primary myelofibrosis. We found that CD146(+) cells sited at the abluminal side of the bone marrow vessels and branching among hematopoietic cells significantly increased in the advanced stages of primary myelofibrosis (p<0.001), paralleling the extent of fibrosis (rho=0.916, p<0.0001) and the microvascular density (r=0.883, p<0.0001). Coherently with a mural cell function, such cells also displayed smooth-muscle actin expression. Our data providing evidence of CD146(+) cell involvement in bone marrow stromal changes occurring in primary myelofibrosis are consistent with the capability of these cells to participate in fiber deposition, angiogenesis, and bone formation. They could also represent rationale for new therapies targeting the bone marrow stroma in primary myelofibrosis.

Associations between Notch-2, Akt-1 and HER2/neu expression in invasive human breast cancer: a tissue microarray immunophenotypic analysis on 98 patients.

OBJECTIVE: We aimed to investigate the existence of associations between well-established and newly recognized biological and phenotypic features of breast cancer involved in tumor progression and prognosis. METHODS: Ninety-eight cases of invasive breast cancer were assessed for the immunohistochemical expression of estrogen and progesterone receptors, Ki-67, HER2, Akt-1, and Notch-2, using the tissue microarray technique. Data regarding tumor histotype, histological grade, tumor size and lymph node status were collected for each patient and included in the analysis. RESULTS: Several significant associations between histological and/or immunophenotypic features came from the analysis of our data. Positive associations were observed between estrogen and progesterone receptors, tumor grade and proliferation index, tumor grade and HER2, Akt-1 and estrogen receptors, and Notch-2 and HER2. Inverse associations were noted between hormone receptors and tumor grade, hormone receptors and HER2, Akt-1 and tumor grade, and Akt-1 and nodal invasion. CONCLUSIONS: Our results, showing the existence of a number of estrogen receptor-positive tumors with Akt-1 expression, better degree of differentiation, and no lymph node involvement, along with the presence of HER2-positive tumors with strong Notch-2 expression, support the role of Notch and Akt in breast cancer progression and suggest that they may also represent new appealing therapeutic targets.

Response to antiviral therapy and hepatic expression of cyclooxygenases in chronic hepatitis C.

OBJECTIVES: The aims of this study were to investigate the expression of cyclooxygenase-1 and cyclooxygenase-2 (COX-1 and COX-2) in chronic hepatitis C (CHC) by immunohistochemistry, based on the hypothesis that COXs expression could vary according to genotype, viral load, liver steatosis, BMI and response to therapy and to determine whether the addition of selective COX inhibitors could have a rationale in increasing the efficacy of antiviral therapy. METHODS: We used 35 formalin-fixed, paraffin-embedded liver tissue samples obtained by needle biopsy from patients with CHC (17F/18M) with one of two types of genotype (1b and 3a). The presence of COX-1 and COX-2 in the cytoplasm of hepatocytes was scored on the basis of: (i) maximum intensity; (ii) dominant intensity; and (iii) extent. RESULTS: No significant differences were found in COX-1 and COX-2 expression in CHC patients divided according to genotype or according to the type of response to combination therapy with pegylated-interferon and ribavirin. The only significant correlations were observed between the dominant intensity of COX-2 and the presence of histological steatosis (P<0.01) and an inverse correlation between COX-2 extent and the viral load (P<0.02). CONCLUSIONS: The lack of correlation between COXs tissue expression and response to antiviral treatment suggests that there is no rationale to adding selective COX inhibitors to increase the efficacy of antiviral therapy, although further studies on larger patient populations are needed. On the contrary, there is a potential application for their use in the prevention and treatment of liver steatosis.

Value of bone marrow biopsy in the diagnosis of essential thrombocythemia.

BACKGROUND AND OBJECTIVES: Essential thrombocythemia (ET) is a Philadelphia chromosome-negative chronic myeloproliferative disorder (CMPD) whose diagnosis, according to the Polycythemia Vera Study Group (PVSG) criteria, does not include histopathological data. The new WHO classification of CMPD has supplied new diagnostic guidelines which highlight the value of histopathology and facilitate a more precise differentiation of ET from reactive conditions and other CMPDs. DESIGN AND METHODS: Bone marrow biopsies from 142 adult patients diagnosed with ET according to PVSG criteria were evaluated using the new WHO classification. Megakaryocyte morphology and arrangement, amount of fibrosis and a clustering index were studied along with determination of microvessel density (MVD), amount of CD34+ cells and percentage of MIB-1+ cells and megakaryocytes. The last value, indicated as megakaryocyte proliferation index (MPI), was determined and expressed as a percentage of the counted cells. RESULTS: According to WHO criteria the 142 biopsies were classified as follows: ET (21%); Idiopathic myelofibrosis (IMF) grade 0 (30%); IMF-1 (34%); IMF-2 (10%) ET/IMF-0 (5%). A significant difference (p<0.001) was observed between clustering index values in ET and IMF cases. A peculiar proliferative feature of megakaryocytes, defined coupling, was detected in all ET cases. MVD was more pronounced and the number of CD34+ cells higher in cases of IMF than in cases of ET (p <0.005; p = 0.001, respectively) and MVD significantly correlated with the extent of fibrosis (r=0.861). ET cases showed the lowest values of proliferation; IMF-0 and IMF-1 showed higher values while a decrease of MPI was observed in IMF-2 in accordance with the increase of fibrosis. INTERPRETATION AND CONCLUSIONS: In the diagnosis of thrombocythemic disorders, a multidisciplinary approach must include the evaluation of bone marrow biopsies. Some histopathological criteria, along with the use of markers related to activity and proliferation such as CD34 and MIB-1, underline the biological differences between ET and prefibrotic states of IMF.