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Luis Chiriboga

Publications and source records attributed to Luis Chiriboga.

At least 19 recordsLinked to original sources
PubMed2026

Yes-Associated Protein (YAP)1 and β-Catenin Immunohistochemistry as a Surrogate Marker for GTF2I-Mutant Type A/AB Thymomas.

Thymomas are rare thymic epithelial tumors classified by the World Health Organization into type A/AB thymomas, which commonly harbor GTF2I mutations and behave indolently, and type B thymomas and thymic carcinomas, in which these mutations are less common. Type A and AB thymomas are uniquely enriched for a recurrent somatic hotspot mutation in GTF2I p. L424H; yet, this gene is rarely included in clinical sequencing panels, limiting its diagnostic utility. Yes-associated protein (YAP)1, the principal effector of the Hippo signaling pathway, and β-catenin, the central transcriptional effector of the Wnt pathway, have emerging roles in thymoma biology; however, their relationship to GTF2I mutation status and histologic subtype has not been systematically characterized. We analyzed The Cancer Genome Atlas thymoma data set and an institutional cohort of 38 thymic epithelial tumors to evaluate YAP1 and β-catenin immunohistochemistry (IHC) as surrogate markers for GTF2I mutation status and histologic classification. In The Cancer Genome Atlas data set, YAP1 and CTNNB1 mRNA expression were markedly elevated in type A/AB thymomas relative to type B and carcinoma subtypes, and GTF2I-mutant tumors exhibited significantly higher YAP1 mRNA expression than GTF2I-wildtype tumors. Targeted next-generation sequencing of our institutional cohort confirmed enrichment of the canonical GTF2I p. L424H hotspot in indolent subtypes. By IHC, both nuclear YAP1 positivity and cytoplasmic β-catenin localization were significantly more frequent in indolent thymomas. Cytoplasmic β-catenin demonstrated high specificity (94%) for indolent histology, supporting its use in diagnostically challenging cases such as type A versus type B3 distinction on small biopsies. YAP1 IHC showed a high negative predictive value for GTF2I mutations, such that a YAP1-negative result reliably excludes a GTF2I-mutant tumor. These findings implicate crosstalk between Hippo and Wnt signaling in GTF2I-mutant thymomas and position YAP1 and β-catenin IHC as accessible, cost-effective surrogates for molecular subtyping in a tumor where standard sequencing panels have limited coverage.

GTF2I↗
PubMed2006

Histologic features are important prognostic indicators in early stages lung adenocarcinomas.

This study attempts to evaluate the clinicopathologic features of mixed subtype adenocarcinomas and the prognostic implications of histopathology classifications. Surgical specimens from 141 patients with clinical stage I or II lung adenocarcinoma during the period 1992-2004 were included. These cases were classified into four groups defined by the extent of the bronchioloalveolar carcinoma component: group I: pure bronchioloalveolar carcinoma; group II: mixed subtype with predominant bronchioloalveolar carcinoma component and < or = 5 mm invasive component; group III: mixed subtype with bronchioloalveolar carcinoma component and > 5 mm invasive component; group IV: invasive carcinoma with no bronchioloalveolar carcinoma component. Descriptive statistics were used to examine the groups with respect to age, tumor size, lymph node metastasis, and Ki-67 and p53 expression levels. Death rate for the groups was obtained by patient's charts and from the National Death Index database. The population was similar in age, tumor size and lymph node metastasis. Immunohistochemical results showed that the mean Ki-67 labeling and the amount of p53 overexpression had the same trend of increasing mean values or positive results from groups I to IV. The reported proportion of deaths ranged from 0% for groups I and II, 20% in patients with predominant invasive component with bronchioloalveolar carcinoma (group III), and 18% in patients with invasive carcinomas and no bronchioloalveolar carcinoma component (group IV). The difference between the proportion of patients with reported deaths in the time period of this study in the combined greater than 5 mm+pure invasive groups (groups III, IV), and the < 5 mm + noninvasive groups (groups I, II) is statistically significant. These results suggest that histological features may be useful in defining categories of lung adenocarcinomas with differing survival and prognostic features. These results are helpful in defining a subcategory of 'minimally invasive adenocarcinoma', which has features similar to bronchioloalveolar carcinoma.

Adenocarcinoma↗
PubMed2006

DC-LAMP stains pulmonary adenocarcinoma with bronchiolar Clara cell differentiation.

DC-LAMP is a molecule expressed in mature dendritic cells, but its mRNA is also found in the lung. This study compares the immunostaining spectrum of PE-10, an antisurfactant protein monoclonal antibody; thyroid transcription factor-1 (TTF-1); and DC-LAMP in normal and neoplastic lung in an attempt to characterize the cell type(s) that express DC-LAMP. Electron microscopy was used to define cell types. DC-LAMP marks pulmonary adenocarcinomas that show Clara cell characteristics by electron microscopy. In contrast, PE-10 labels tumors that have Clara cell and type II pneumocyte differentiation. DC-LAMP staining was lost in solid type adenocarcinomas but persisted in well-differentiated areas. CC-10, an antibody that marks Clara cells, was also positive in tumors that labeled for DC-LAMP. There was no prognostic difference in tumors that reacted with DC-LAMP. DC-LAMP and CC-10 reactivity was also observed in endometrial adenocarcinomas but not in other tumor types.

Adenocarcinoma↗
PubMed2006

Multiplex short tandem repeat DNA analysis confirms the accuracy of p57(KIP2) immunostaining in the diagnosis of complete hydatidiform mole.

Detailed histopathologic examination remains to be the basis for the diagnosis of hydatidiform mole (HM). However, poor sampling, necrosis, and earlier uterine evacuation can lead to uncertainty in the diagnosis. Also, the criteria are subjective, resulting in considerable interobserver variability. The p57(KIP2) gene is paternally imprinted and maternally expressed, and the presence of its protein product serves as a surrogate marker for the nuclear maternal genome. Because a complete HM (CHM) is the only type of conceptus lacking a maternal contribution, p57(KIP2) immunostaining is correspondingly absent, whereas it is present in CHM mimics. Although analysis of DNA microsatellite polymorphisms is a reliable method for the diagnosis and classification of HM, it is not universally available. To assess the relative accuracy of p57(KIP2) immunostaining and molecular diagnosis by nuclear DNA microsatellite polymorphisms in discriminating CHM from its mimics, we analyzed archival tissue from 33 case patients (7 with a definitive diagnosis of CHM, 16 with a possible diagnosis of HM, and 10 with normal placentas) by both methods. Concordant results were obtained in all cases, and p57(KIP2) immunostaining accurately identified all cases of CHM from the groups with a definitive or possible diagnosis of HM. p57(KIP2) immunohistochemistry is a time- and cost-effective means of distinguishing CHM from its mimics in challenging cases.

Alleles↗
PubMed2006

Spatial differences in biologic activity of large uterine leiomyomata.

OBJECTIVE: To evaluate the growth pattern of the large uterine leiomyomata (ULM), we examined the spatial gene distributions, vessel density, proliferative activity, and hyaline degeneration. DESIGN: Tissue sections from three-dimensional large ULM, matched myometrium, and small ULM were collected and microarrayed. The spatial difference of the tumor activity was mapped in large ULM. SETTING: University clinical research laboratory. PATIENT(S): Hysterectomy specimens from 7 patients with large (>10 cm) ULM and 3 patients with large (>10 cm) uterine leiomyosarcomas. INTERVENTION(S): Tissue microarray analysis by the immunohistochemistry. MAIN OUTCOME MEASURE(S): Selected gene products, vessel density, and the percentage of hyaline degeneration were all scored in tissue cores/sections of large and small ULM against matched myometrium. RESULT(S): We found that there was a spherical spatial difference of the tumor activities in large ULM. The tumor region next to the periphery, the most biologically active zone, demonstrated higher levels of gene expression, a higher density of vessels, a higher proliferative rate and a lower level of hyaline degeneration. The large ULM have higher levels of gene products (except for estrogen and progesterone receptors) than small ULM. CONCLUSION(S): In comparison of the spatial patterns of the gene activity between the large ULM and the large uterine leiomyosarcoma, the large ULM illustrate a growth pattern of nutritional dependence.

Adult↗
PubMed2006

PAX2: a reliable marker for nephrogenic adenoma.

Nephrogenic adenoma is a rare lesion of the urinary tract. The diagnosis usually is straightforward when characteristic microscopic and clinical findings are present, and the entity is familiar. However, misdiagnosis, in particular of adenocarcinoma of the prostate gland, may occur. Immunohistochemical stains often are needed to make such a distinction, but currently available markers offered only partial help. It recently was demonstrated that nephrogenic adenoma in renal transplant patients originated from the renal tubular epithelium. This newly proved, but long sought information may be helpful in the differential diagnosis of nephrogenic adenoma. In this study, we investigated the expression of a renal transcription factor, PAX2, in 39 nonrenal transplant-related nephrogenic adenomas, 100 adenocarcinomas of the prostate gland, and 47 urothelial carcinomas of the urinary tract. A strong and distinct nuclear staining of PAX2 was found in all 39 cases of nephrogenic adenoma (100%), but not in normal prostate tissue, normal urothelium, adenocarcinomas of the prostate gland, and invasive urothelial carcinomas. Focal CD10 was detected in six of 13 nephrogenic adenomas in the superficial papillary component and in normal prostate epithelium, normal urothelium, lymphocytes, adenocarcinoma of the prostate gland, and urothelial carcinoma. There was no uroplakins detected in nephrogenic adenoma. Therefore, these findings are suggesting that nephrogenic adenoma in nonrenal transplant patients may also arise from the renal epithelium, as did the comparable lesions after transplantation. PAX2 is a specific and sensitive immunohistochemical marker in identification and differential diagnosis of nephrogenic adenoma.

Adenoma↗
PubMed2005

Ethnic differences in expression of the dysregulated proteins in uterine leiomyomata.

BACKGROUND: Black ethnicity is one of the risk factors for uterine leiomyomata (ULM). Little is known about the ethnic differences in leiomyoma-associated gene products in women with uterine leiomyomata. METHODS: A total of 120 hysterectomies with ULM were collected from black, Asian, Hispanic and white women (30 cases from each group). Twenty-two gene products were selected for the study. The expressions of the selected dysregulated gene products were measured by the semiquantification and the immunoscores were normalized by matched myometrium. RESULTS: The relative expressions of progesterone receptor A (PR-A) (up-regulation), retinoid acid receptor alpha (down-regulation), and retinoid X receptor alpha (RXRalpha) (no change) in leiomyomata compared to normal myometrium in black women were significantly different compared to other ethnic groups (P < 0.05). About one-third of ULM from black women subclustered together in association with a group of up-regulated gene products. Many other gene products, including local growth factors, insulin-like growth factor (IGF)-signalling proteins, and cell proliferation markers, were dysregulated in ULM but showed non-significant differences between the ethnic groups. CONCLUSIONS: There are substantial differences of the sex steroid receptors and other nuclear receptors between black women and other ethnic groups. Based on tissue microarray data, there are at least two broad groups of leiomyomata presented by the dysregulation of different groups of gene products. One is dominated by up-regulation of amplified in breast cancer 1, CD24, hamartin, human mobility group gene 2, IGF2, PR-A and RXR, and the other is characterized by up-regulation of epithelial growth factor receptor, down-regulation of hamartin, PR-A and tuberin.

Black or African American↗
PubMed2005

Stromal cell-derived factor-1alpha and CXCR4 expression in hemangioblastoma and clear cell-renal cell carcinoma: von Hippel-Lindau loss-of-function induces expression of a ligand and its receptor.

The genetic hallmark of hemangioblastomas and clear cell-renal cell carcinomas (CC-RCCs) is loss-of-function of the von Hippel-Lindau (VHL) tumor suppressor protein. VHL is required for oxygen-dependent degradation of hypoxia-inducible factor-1alpha (HIF-1alpha). In hemangioblastomas and CC-RCCs, HIF-1alpha is constitutively overexpressed leading to increased transcription of HIF-1-regulated genes, including vascular endothelial growth factor (VEGF). Because loss of VHL function is associated with increased expression of the chemokine receptor CXCR4 in CC-RCCs, we investigated the expression of HIF-1alpha, CXCR4, and its ligand stromal cell-derived factor-1alpha (SDF-1alpha) in hemangioblastomas and CC-RCCs. Immunohistochemistry revealed overexpression of both CXCR4 and SDF-1alpha within tumor cells and endothelial cells of hemangioblastomas and CC-RCCs. HIF-1alpha was detected in tumor cell nuclei of both hemangioblastomas and CC-RCCs. A specific ELISA showed that hemangioblastomas and CC-RCCs expressed SDF-1alpha protein at levels that were significantly higher than those found in normal tissue. Analysis of the VHL-null RCC line 786-0 revealed that SDF-1alpha mRNA levels were 100-fold higher than in a subclone transfected with the wild-type VHL gene. Expression of CXCR4 and SDF-1alpha mRNA was significantly decreased in HIF-1alpha-null compared with wild-type mouse embryo fibroblasts (MEFs). ELISA and Western blot studies for SDF-1alpha and CXCR4 protein expression confirmed the RNA findings in RCC lines and MEFs. These results suggest that loss-of-function of a single tumor suppressor gene can up-regulate the expression of both a ligand and its receptor, which may establish an autocrine signaling pathway with important roles in the pathogenesis of hemangioblastoma and CC-RCC.

Adenocarcinoma, Clear Cell↗
PubMed2005

Expression profile of the tumorigenic factors associated with tumor size and sex steroid hormone status in uterine leiomyomata.

OBJECTIVE: To use tissue microarray in combination with dendrogram cluster analysis to characterize some potential tumorigenic factors in association with tumor size and sex steroid hormone status in uterine leiomyomata. DESIGN: Expression analysis of 21 selected potential tumorigenic factors in 60 patients with uterine leiomyomata. SETTING: University clinical research laboratory. PATIENT(S): Hysterectomy specimens from 60 patients with uterine leiomyomata of different ages and tumor sizes. INTERVENTION(S): Tissue cores from normal myometrium and leiomyomata were examined by immunohistochemistry. MAIN OUTCOME MEASURE(S): Semiquantitative immunointensity was scored and analyzed by net gain and loss between normal myometrium and leiomyomata and integrated into dendrogram cluster tree view. RESULT(S): We found that upregulation of estrogen and progesterone receptors was reverse associated with tumor size. Upregulation of some factors (HMGA2, sex steroid receptor cofactors, proteins in insulin pathway, and CD24) were identified in a group of patients in their later forties, were associated with large fibroids, and were weakly affected by the SSH status (illustrated by endometrial phases and menopause). Downregulation of tuberin and glucocorticoid receptor was mostly isolated in a second group of women at their late reproductive age. CONCLUSION(S): Analyses of the sex steroid hormone receptors and the nonsex steroid hormone factors in leiomyomata and the matched myometrium showed different expression patterns in different tumor sizes and patients' ages. A group of patients in their late forties with the larger leiomyomata contributes largely by upregulation of nonsex steroid hormone factors. Adenomyosis is a protective factor preventing large leiomyomata.

Aged↗
PubMed2005

Fascin-1 expression in papillary and invasive urothelial carcinomas of the urinary bladder.

Fascin-1 is an actin-bundling protein that plays an important role in cell motility and adhesion. The level of fascin-1 is low or undetectable in normal epithelial cells. However, overexpression is reported in transformed epithelial cells and in several common types of carcinomas [Bioessays. 2002;24:359-361]. Up-regulation of fascin-1 is associated with higher grades and with aggressive tumors with poorer prognoses. We found no report on the role or the protein expression of fascin-1 in urothelial carcinomas (UCs) of the urinary bladder. In this study, we examined by immunohistochemistry the expression of fascin-1 in the normal human transitional epithelium, benign vesical lesions, and different types of UCs. We found no detectable fascin-1 in the normal transitional epithelium. There was no increase of fascin-1 expression in cystitis cystica, cystitis glandularis, nephrogenic adenoma (n = 10), inverted papilloma (n = 5), and classic exophytic papilloma (n = 4) or in adjacent transitional epithelia associated with these conditions. Patchy or diffusely weak fascin-1 expression was observed in 42% (5/12) of superficial papillary UCs (Ta), and 95% (19/20) of invasive UCs (T2 or higher) demonstrated diffuse strong staining for fascin-1. The microinvasive foci in the lamina propria of UC (T1, n = 8) were also positive for fascin-1, although they were not as strongly stained as in the deeply invasive tumors. Interestingly, the neoplastic cells in the tips of microinvasive carcinomas were distinctly positive for fascin-1. There were significant numbers of fascin-1-positive cells (>50% of the neoplastic cells) in UCs in situ (n = 10). These findings suggest an association between increased fascin-1 expression and increased invasiveness of carcinomas in the urinary bladder.

Adult↗
PubMed2005

Downregulation of major histocompatibility complex antigens in invading glioma cells: stealth invasion of the brain.

Invasion into surrounding brain tissue is a fundamental feature of gliomas and the major reason for treatment failure. The process of brain invasion in gliomas is not well understood. Differences in gene expression and/or gene products between invading and noninvading glioma cells may identify potential targets for new therapies. To look for genes associated with glioma invasion, we first employed Affymetrix microarray Genechip technology to identify genes differentially expressed in migrating glioma cells in vitro and in invading glioma cells in vivo using laser capture microdissection. We observed upregulation of a variety of genes, previously reported to be linked to glioma cell migration and invasion. Remarkably, major histocompatiblity complex (MHC) class I and II genes were significantly downregulated in migrating cells in vitro and in invading cells in vivo. Decreased MHC expression was confirmed in migrating glioma cells in vitro using RT-PCR and in invading glioma cells in vivo by immunohistochemical staining of human and murine glioblastomas for beta2 microglobulin, a marker of MHC class I protein expression. To the best of our knowledge, this report is the first to describe the downregulation of MHC class I and II antigens in migrating and invading glioma cells, in vitro and in vivo, respectively. These results suggest that the very process of tumor invasion is associated with decreased expression of MHC antigens allowing glioma cells to invade the surrounding brain in a 'stealth'-like manner.

Animals↗
PubMed2005

Expression profile of tuberin and some potential tumorigenic factors in 60 patients with uterine leiomyomata.

Human uterine leiomyomata are the most common tumors in women of reproductive age. The pathogenesis of leiomyomata remains unknown. An animal model of Eker rats with deleted tuberous sclerosis complex gene 2 (tuberin) shows increased incidence of leiomyomata. The role of tuberin in human leiomyomata is unknown. In this study, we designed a tissue microarray with tissue cores of leiomyomata and the matched myometrium from 60 hysterectomy specimens. We examined the expression of tuberin and tuberous sclerosis complex gene 1 product hamartin, proteins of the insulin-signaling pathway, steroid receptors and some of their cofactors, and human mobility group gene A2 by immunohistochemistry. We found that nearly half of the cases displayed either reduction or loss of tuberin in leiomyomata compared with matched normal myometrium. No change of hamartin was noted. Furthermore, a significant reduction of glucocorticoid receptor was found in leiomyomata with reduced tuberin. The proteins insulin like growth factor 1, insulin-like growth factor receptor beta, AKT kinase, and phosphatidylinositol 3-kinase were upregulated. Nearly half of leiomyomata show upregulation of human mobility group gene A2, along with the steroid receptor cofactors. Our findings suggest that there are two broad groups of uterine leiomyomata. One group is associated with an alteration of tuberin and glucocorticoid receptor. The other group is associated with upregulation of human mobility group gene A2 and steroid receptor cofactors.

Adult↗
PubMed2004

Intrahepatic CD4+ cell depletion in hepatitis C virus/HIV-coinfected patients.

Coinfection with HIV and hepatitis C virus (HCV)-specific immune responses, increases hepatic inflammation, accelerates hepatic fibrosis, and is associated with deceased treatment responses. We quantified intrahepatic lymphocyte and hepatocyte phenotypes in HCV-infected patients with (n = 38) and without (n = 41) HIV infection. A single pathologist counted positive cells in 5 portal and 5 lobular areas. Coinfected patients had 6.81 +/- 1.9 fewer CD4 cells per portal field (10.58 +/- 1.12 vs. 4.97 +/- 1.09 cells/high-power field [HPF]; P < 0.001) and 0.48 +/- 0.15 more apoptotic lymphocytes per lobular field (0.16 +/- 0.06 vs. 0.64 +/- 0.15 cell/HPF; P = 0.002) than monoinfected patients. The number of portal CD4 cells was not associated with the peripheral CD4 cell number. Portal and lobular CD8 cells did not differ between the 2 groups. Portal proliferative hepatocytes were increased in coinfected patients with HIV RNA levels of >400 copies/mL (1.13 +/- 0.32 cells/HPF; P = 0.01) compared with those with undetectable HIV RNA (0.46 +/- 0.09 cell/HPF) and monoinfected patients (0.45 +/- 0.08 cell/HPF). In conclusion, HIV coinfection is associated with fewer portal CD4 cells and increased lobular lymphocyte apoptosis that may impact on the natural history of HCV infection.

CD4-Positive T-Lymphocytes↗
PubMed2004

Peripheral CD4(+)CD8(+) T cells are differentiated effector memory cells with antiviral functions.

Although an increased frequency of CD4(+)CD8(+) T cells has been observed in the peripheral blood during viral infections, their role, function, and biologic significance are still poorly understood. Here we demonstrate that the circulating CD4(+)CD8(+) T-cell population contains mature effector memory lymphocytes specific for antigens of multiple past, latent, and high-level persistent viral infections. Upon in vitro antigenic challenge, a higher frequency of CD4(+)CD8(+) than single-positive cells displayed a T helper 1/T cytotoxic 1 (Th1/Tc1) cytokine profile and proliferated. Ex vivo, more double-positive than single-positive cells exhibited a differentiated phenotype. Accordingly, their lower T-cell receptor excision circles (TREC) content and shorter telomeres proved they had divided more frequently than single-positive cells. Consistent with expression of the tissue-homing marker CXCR3, CD4(+)CD8(+) T cells were demonstrated in situ at the site of persistent viral infection (ie, in the liver during chronic hepatitis C). Finally, a prospective analysis of hepatitis C virus (HCV) infection in a chimpanzee, the only animal model for HCV infection, showed a close correlation between the frequency of activated CD4(+)CD8(+) T cells and viral kinetics. Collectively, these findings demonstrate that peripheral CD4(+)CD8(+) T cells take part in the adaptive immune response against infectious pathogens and broaden the perception of the T-cell populations involved in antiviral immune responses.

Animals↗
PubMed2004

Hepatocyte proliferation in chronic hepatitis C: correlation with degree of liver disease and serum alpha-fetoprotein.

AIMS: Hepatocyte proliferation (HP) is an adaptive response to liver injury. The relationships between HP and necroinflammation, fibrosis, and serum alpha-fetoprotein (AFP) levels in chronic hepatitis C virus (HCV) infection, however, are not well understood. METHODS: Proliferative hepatocytes (Ki-67+) were identified using immunohistochemical staining in formalin-fixed, paraffin-embedded liver tissue from 156 HCV RNA-positive patients with different degrees of liver histopathology. Twenty high-power fields (HPFs) in lobular areas were counted in each specimen. RESULTS: HP increased by 1.22 +/- 0.25 cells/HPF per increase in necroinflammation from grade 0 (median: 0.13; range: [0.1-0.5] cells/HPF) through grade 3 (median: 1.80; range: [0.0-25.2] cells/HPF; P=0.002). HP increased by 0.81 +/- 0.20 cells/HPF per increase in fibrosis from stage 0 (median: 0.33; range: [0.0-1.3] cells/HPF) through stage 3 (median: 1.70; range: [0.0-25.2] cells/HPF) and then decreased in stage 4 (to median: 0.90; range: [0.0-5.3] cells/HPF). HP also increased with advancing age (P=0.03). Among patients with advanced liver disease, HP was no higher in patients with elevated serum AFP levels (median: 1.68; range: [0.1-5.3] cells/HPF) than in those with normal serum AFP levels (median: 1.70; range: [0.0-25.2] cells/HPF; P=0.26). CONCLUSIONS: In patients with chronic HCV infection, HP increases with histologic progression of liver disease, but is impaired in cirrhosis. HP was not increased in patients with elevated serum AFP levels.

Adult↗
PubMed2003

Regeneration of hepatocyte 'buds' in cirrhosis from intrabiliary stem cells.

BACKGROUND/AIMS: In massive hepatic necrosis, hepatic stem cells constitute a canal of Hering derived, cytokeratin 19 (CK19) positive 'ductular reaction' (DR). Whether DRs in cirrhosis are activated stem cells (so called 'buds') or biliary metaplasia of cholestatic, injured hepatocytes is still debated. We investigate derivation of intraseptal hepatocytes (ISHs) from DRs and from the biliary tree in cirrhosis. METHODS: Explants of hepatitis B and C, alcohol, primary biliary cirrhosis and primary sclerosing cholangitis-related cirrhosis were examined. ISHs were quantified and their associations with DRs and cholestasis recorded. 3D-reconstruction of ISHs and nearby bile ducts was performed in blocks from hepatitis C and primary sclerosing cholangitis cirrhosis. RESULTS: Seven hundred seventy five/830 (94%) ISHs were associated with CK19 positive DRs. ISHs without ductular reactions were more likely to show cholestatic features (P<0.0001). In 3D, ISHs were seen to bud directly from the biliary tree. In summary: ISHs: (1) are usually associated with stem cell-like DRs; (2) are rarely cholestatic, leaving the associated DRs unexplained; and (3) are linked to the biliary tree in 3D. Dynamic proliferation rates in hepatitis C over time suggest that hepatocyte replication diminishes in late stages, with an associated activation of the biliary stem cell compartment. CONCLUSIONS: We therefore suggest that the biliary tree, from at least its smaller branches up to the canals of Hering, are composed of or at least harbor facultative hepatic stem cells, and that ISH largely represent 'buds' of newly formed hepatocytes.

Biliary Tract↗