Nucleus pulposus phenotypic markers to determine stem cell differentiation: fact or fiction?

Progress in mesenchymal stem cell (MSC) based therapies for nucleus pulposus (NP) regeneration are hampered by a lack of understanding and consensus of the normal NP cell phenotype. Despite the recent consensus paper on NP markers, there is still a need to further validate proposed markers. This study aimed to determine whether an NP phenotypic profile could be identified within a large population of mature NP samples.qRT-PCR was conducted to assess mRNA expression of 13 genes within human non-degenerate articular chondrocytes (AC) (n=10) and NP cells extracted from patients across a spectrum of histological degeneration grades (n=71). qRT-PCR results were used to select NP marker candidates for protein expression analysis.Differential expression at mRNA between AC and non-degenerate NP cells was only observed for Paired Box Protein 1 (PAX1) and Forkhead box F1 (FOXF1). In contrast no other previously suggested markers displayed differential expression between non-degenerate NP and AC at mRNA level. PAX1 and FOXF1 protein expression was significantly higher in the NP compared to annulus fibrosus (AF), cartilaginous endplate (CEP) and AC. In contrast Laminin-5 (LAM-332), Keratin-19 (KRT-19) and Hypoxia Inducible Factor 1 alpha (HIF1α) showed no differential expression in NP cells compared with AC cells.A marker which exclusively differentiates NP cells from AF and AC cells remains to be identified, raising the question: is the NP a heterogeneous population of cells? Or does the natural biological variation during IVD development, degeneration state and even the life cycle of cells make finding one definitive marker impossible?

In vitro differentiation of hepatic progenitor cells from mouse embryonic stem cells induced by sodium butyrate

Recently it was shown that embryonic stem (ES) cells could differentiate into hepatocytes both in vitro and in vivo, however, prospective hepatic progenitor cells have not yet been isolated and characterized from ES cells. Here we presented a novel 4-step procedure for the differentiation of mouse ES cells into hepatic progenitor cells and then hepatocytes. The differentiated hepatocytes were identified by morphological, biochemical, and functional analyses. The hepatic progenitor cells were isolated from the cultures after the withdrawal of sodium butyrate, which was characterized by scant cytoplasm, ovoid nuclei, the ability of rapid proliferation, expression of a series of hepatic progenitor cell markers, and the potential of differentiation into hepatocytes and bile duct-like cells under the proper conditions that favor hepatocyte and bile epithelial differentiation. The differentiation of hepatocytes from hepatic progenitor cells was characterized by a number of hepatic cell markers including albumin secretion, upregulated transcription of glucose-6-phosphatase and tyrosine aminotransferase, and functional phenotypes such as glycogen storage. The results from our experiments demonstrated that ES cells could differentiate into a novel bipotential hepatic progenitor cell and mature into hepatocytes with typical morphological, phenotypic and functional characteristics, which provides an useful model for the studies of key events during early liver development and a potential source of transplantable cells for cell-replacement therapies.

Smoking accelerates pancreatic cancer progression by promoting differentiation of MDSCs and inducing HB-EGF expression in macrophages

Smoking is an established risk factor for pancreatic cancer (PC), but late diagnosis limits the evaluation of its mechanistic role in the progression of PC. We used a well-established genetically engineered mouse model (LSL-K-ras(G12D)) of PC to elucidate the role of smoking during initiation and development of pancreatic intraepithelial neoplasia (PanIN). The 10-week-old floxed mice (K-ras(G12D); Pdx-1cre) and their control unfloxed (LSL-K-ras(G12D)) littermates were exposed to cigarette smoke (total suspended particles: 150 mg/m(3)) for 20 weeks. Smoke exposure significantly accelerated the development of PanIN lesions in the floxed mice, which correlated with tenfold increase in the expression of cytokeratin19. The systemic accumulation of myeloid-derived suppressor cells (MDSCs) decreased significantly in floxed mice compared with unfloxed controls (P<0.01) after the smoke exposure with the concurrent increase in the macrophage (P<0.05) and dendritic cell (DCs) (P<0.01) population. Further, smoking-induced inflammation (IFN-γ, CXCL2; P<0.05) was accompanied by enhanced activation of pancreatic stellate cells and elevated levels of serum retinoic acid-binding protein 4, indicating increased bioavailability of retinoic acid which contributes to differentiation of MDSCs to tumor-associated macrophages (TAMs) and DCs. TAMs predominantly contribute to the increased expression of heparin-binding epidermal growth factor-like growth factor (EGFR ligand) in pre-neoplastic lesions in smoke-exposed floxed mice that facilitate acinar-to-ductal metaplasia (ADM). Further, smoke exposure also resulted in partial suppression of the immune system early during PC progression. Overall, the present study provides a novel mechanism of smoking-induced increase in ADM in the presence of constitutively active K-ras mutation.

Universal markers of thyroid malignancies: galectin-3, HBME-1, and cytokeratin-19

Difficulties in diagnosis of thyroid lesions, even with histologic analysis, are well known. This study has been carried on to evaluate the role of immunohistochemical markers including galectin-3, Hector Battifora mesothelial cell-1 (HBME-1), and cytokeratin-19 in the diagnosis and differential diagnosis of benign and malignant thyroid lesions. The expressions of galectin-3, HBME-1, and cytokeratin-19 were tested in formalin-fixed, paraffin-embedded tissues from 458 surgically resected thyroid lesions including non-neoplastic and neoplastic lesions. Immunostaining with standard avidin-biotin complex technique was performed by using monoclonal antibodies. In malignant neoplastic thyroid lesions, galectin-3, HBME-1, and cytokeratin-19 were diffusely expressed in general. Diffuse expression rates of these three markers were 72.3% (47/65), 70.7% (46/65), and 76.9% (50/65), respectively. The use of galectin-3, HBME-1, and cytokeratin-19 may provide significant contributions in the differential diagnosis of malignant thyroid tumors. Although focal galectin-3, HBME-1, and cytokeratin-19 expression may be encountered in benign lesions, diffuse positive reactions for these three markers are characteristic of malignant lesions. It has concluded that cytokeratin-19 alone and its combinations with other markers were more sensitive in accurate diagnosis of papillary carcinoma than the other combinations; meanwhile, there were similar results for follicular carcinomas with HBME-1 alone and its combinations.

Prospero-related homeobox 1 (Prox1) is a stable hepatocyte marker during liver development, injury and regeneration, and is absent from "oval cells"

The aim of this study was to analyse the changes of Prospero-related homeobox 1 (Prox1) gene expression in rat liver under different experimental conditions of liver injury, regeneration and acute phase reaction, and to correlate it with that of markers for hepatoblasts, hepatocytes, cholangiocytes and oval cells. Gene expression was studied at RNA level by RT-PCR, and at protein level by immunohistochemistry. At embryonal stage of rat liver development (embryonal days (ED) 14-16) hepatoblasts were found to be Prox1(+)/Cytokeratin (CK) 19(+) and alpha-fetoprotein (AFP)(+), at this stage Prox1(-)/CK19(+)/AFP(-) small cells (early cholangiocytes?) were identified. In fetal liver (ED 18-22) hepatoblasts were Prox1(+)/CK19(-)/AFP(+). CK7(+) cholangiocytes were detected at this stage, and they were Prox1(-)/AFP(-). In the adult liver hepatocytes were Prox1(+)/CK19(-)/CK7(-)/AFP(-), cholangiocytes were CK19(+) and/or CK7(+) and AFP(-)/Prox1(-). In models of liver damage and regeneration Prox1 remained a stable marker of hepatocytes. After 2-acetyl-aminofluorene treatment with partial hepatectomy (AAF/PH) the amount of Prox1 specific transcripts was low in the liver, when CK19 and AFP gene expression was high, and at no time point AFP(+)/CK19(+ )"oval cells" were found to be Prox1(+). However, a few Prox1(+)/CK19(+) and a few Prox1(+)/CK7(+ )cells were identified in the liver of AAF/PH-animals, which may represent precursors of hepatocytes, or a precancerous state.

Distinctive molecular composition of human gingival interdental papilla

BACKGROUND

Gingiva is composed of attached and marginal (free) gingiva and interdental papilla. Increasing esthetic demands in dentistry have created a need to restore all parts of the gingiva. However, the interdental papilla has limited regeneration potential compared to other parts of the gingiva. It also is more susceptible to gingival overgrowth, suggesting that it has distinct cellular and molecular properties from other parts of the gingiva. Very little is known about the possible differences in the molecular composition of different parts of the gingiva.

METHODS

We compared the expression of a set of key molecules in interdental papilla and marginal gingiva from seven healthy subjects by immunohistochemical staining.

RESULTS

In the interdental papilla, immunoreactivity for integrin alphavbeta6 and cytokeratin 19 in the oral epithelium was significantly higher than in marginal gingiva. Expression of type I procollagen, extra domain A (EDA) and extra domain B (EDB) fibronectin isoforms, tenascin-C, transforming growth factor-beta (TGF-beta), connective tissue growth factor (CTGF), and the signaling molecule son-of-sevenless (SOS)-1 also were increased in the interdental papilla. The expression of small leucine-rich proteoglycans decorin, biglycan, fibromodulin, and lumican in the interdental papilla was partially different from the marginal gingiva.

CONCLUSIONS

Molecular composition of the interdental papilla is distinct from marginal gingiva. Increased expression of molecules normally induced in wound healing (alphavbeta6 integrin, fibronectin-EDB and -EDA, tenascin-C, type I procollagen, TGF-beta, CTGF, and SOS-1) suggests that the cells in the interdental papilla are in an activated state and/or inherently display a specific phenotype resembling wound healing.

Serum Cyfra 21.1 and galectin-3 protein levels in relation to immunohistochemical cytokeratin 19 and galectin-3 expression in patients with thyroid tumors

PURPOSE

The aim of this study was to assess the clinical utility of circulating preoperative Cyfra 21.1 [soluble fragment of cytokeratin (CK) 19] and galectin-3 (gal-3) in patients with thyroid tumors, to compare their serum values with tissue expression and to analyze the prognostic significance of these markers in relation to the clinical status of postsurgical differentiated thyroid carcinoma (DTC) patients.

PATIENTS

Concentrations of Cyfra 21.1 and gal-3 were evaluated by immunoassays in sera of 9 healthy subjects, 97 preoperative patients with diverse thyroid tumors (10 FTA, 63 PTC, 11 FTC, 5 PDTC, 4 ATC, 4 LNM) and 25 postoperative DTC patients (14 remissions and 11 metastases).

RESULTS

Low Cyfra 21.1 values were found in all subgroups, but with a tendency toward higher values in poorly differentiated DTC patients. Compared to the control (0.23 ng/mL), serum levels of gal-3 were significantly elevated in patients with thyroid tumors but with overlapping between adenoma (4.16 ng/mL) and carcinoma (3.85, 4.37, 4.64, 6.07 ng/mL for PTC, PDTC, ATC and LNM, respectively). The tissue expression of CK19 and gal-3 was immunohistochemically determined on 45 matched paraffin-embedded sections. Most thyroid carcinomas showed positive CK19 (27/35) and gal-3 immunostaining (31/35), while adenomas were mostly immunonegative (8/10 and 7/10, respectively). However, there was no significant correlation between their serum and tissue levels. Clinical status of postoperative DTC patients had no influence on serum concentrations of the tested markers.

CONCLUSIONS

While CK19 and gal-3 are accurate as tissue markers, their serum levels could not be used as reliable markers for identification of thyroid malignancy or in thyroid cancer follow-up. On the other hand, a tendency toward higher serum levels of Cyfra 21.1 in the small number of PDTC patients examined adds weight to previous reports postulating a role for cytokeratins in predicting a high degree of malignancy.

Quantitative detection of circulating epithelial cells by Q-RT-PCR

INTRODUCTION

It has been shown that the quantity of circulating tumor cells (CTCs) in breast cancer patients is an independent predictor of survival and treatment response. Real time quantitative reverse transcriptase PCR (Q-RT-PCR) is a sensitive technique for detection of CTCs. Our aim was to investigate whether the technique can be used also to quantitate these CTCs.

METHODS

We tested cytokeratin 19 (CK19), maspin, mammaglobin, GAPDH and RPL19 genes for their level of expression and linearity of amplification in serial dilutions of RNA extracted from the MDA-MB-231, UACC-812, T47D and HS578T breast cancer cell lines. To simulate CTCs, serial dilutions of cultured T47D and HS578T cells were added to peripheral blood from healthy volunteers. The samples were subjected to enrichment, RNA extraction and Q-RT-PCR.

RESULTS

CK19 was reliably expressed in all four cell lines with a linear relationship between the quantity of added cells and the amount of CK19 RNA. The lower limit of reliable detection was 5 cells per sample, which corresponds to a concentration of 0.7 cell/ml in 7.5 ml of blood or would translate to a lower CTC concentration in a larger volume of blood.

CONCLUSION

This technique may prove useful for high throughput comparative quantification of CTCs in individual patients during treatment and subsequent follow up for research and clinical management purposes.

Immunohistochemical markers in the diagnosis of papillary thyroid carcinomas: The promising role of combined immunostaining using HBME-1 and CD56

We aimed to evaluate the expression and diagnostic value of five immunohistochemical markers (HBME-1, Galectin-3, CK19, CD56 and p63) in a very large series of unequivocal papillary thyroid carcinoma (PTC) cases, including both the classic (CPTC) and the follicular variant (FVPTC). We performed an immunohistochemical analysis on a tissue micro-array of 204 PTCs (98 CPTCs, 90 FVPTCs, and 16 other variants). HBME-1 was the most sensitive marker, staining 95.9% of CPTCs and 81.1% of FVPTCs. CD56, a marker whose expression is reduced or absent in thyroid carcinoma, revealed a negative, "malignant" profile in 93.9% of CPTCs and 73.3% of FVPTCs. Galectin-3, CK19 and p63 were positive in 64.7%, 45.6% and 6.9% of PTCs, respectively. The immunopanel consisting of HBME-1, CD56 and/or CK19 reached the highest sensitivity (95.6%). The co-expression of 2 or more proteins was observed in 88.2% of PTCs, with HBME-1 and CD56 being the most frequent positive association (79.4%). We report a new panel of antibodies consisting of HBME-1, CK19 and CD56 that was found to be highly sensitive for both CPTC and FVPTC. This panel could be recommended as a supplement to the morphological criteria in the diagnosis of difficult FVPTC cases.

The diagnostic accuracy of the immunocytochemical markers in the pre-operative evaluation of follicular thyroid lesions

Aim of the study was to consider the diagnostic accuracy of galectine-3 (GAL3) in the pre-operative cytological evaluation of follicular lesions.

MATERIALS AND METHODS

We retrospectively evaluated 100 patients suffering from thyroid nodular disease submitted to thyroidectomy from 2006 to 2007 in our Institution. Before surgery all patients underwent fine needle aspiration biopsy. The immunocytochemical analysis was performed on fine needle aspiration specimens using species-specific monoclonal antibodies and a biotin-free detection system. Based on preoperative cytological reports, 40 patients had pre-operative malignant results, and 60 patients (46 females and 14 males) showed follicular lesions. The sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy of GAL3 was evaluated.

STATISTICAL ANALYSIS

Chi-square test was used to compare frequencies of GAL3 expression between the different hystopathological groups.

RESULTS

GAL3 proved to have 55% sensitivity, 100% specificity, 70% negative predictive value, and 78% diagnostic accuracy. The GAL3 expression in neoplastic and benign lesions was significantly different (GAL3+ in 16 out of 29 neoplastic lesions, GAL3+ 0 out of 31 benign lesions, p<0.01). Even comparing the GAL3 positivity between the follicular adenomas (0 GAL3+ out of 20) and the group of follicular carcinomas (5 GAL3+ out of 6), we found a statistically significant difference (p<0.01).

CONCLUSIONS

Based on the data from our experience, the patients with a cytological diagnosis of GAL3 positive follicular neoformation should be referred for surgery without any further immunocytological testing.

Diagnostic value of mesothelin in pleural fluids: comparison with CYFRA 21-1 and CEA

CYFRA 21-1 and CEA have been applied for the differential diagnosis of malignant pleural mesothelioma (MPM). The soluble mesothelin-related peptide (SMRP) has been proposed as a specific marker for distinguishing MPM from benign diseases and other malignancies in pleural effusions (PEs). In this study, we evaluated the usefulness of SMRP in PEs in the detection of mesotheliomas by comparing it with that of CYFRA 21-1, CEA, and with cytological examination. One hundred and seventy-seven consecutive patients (57 MPM, 64 metastatic tumors, and 56 benign diseases) were evaluated using commercial tests. The performance of the markers was analyzed by standard ROC analysis methods, using the area under a ROC curve (AUC) as a measure of accuracy. CYFRA 21-1 better differentiated malignant from benign effusions. The corresponding area under the receiver operating characteristic curve was 0.87, while it was 0.74 for SMRP and 0.64 for CEA (p < 0.001). Conversely, SMRP differentiated MPM from all other PEs better than both CYFRA 21-1 and CEA (AUC = 0.84, 0.76, and 0.32, respectively, p = 0.003). Low levels of CEA were associated with a MPM diagnosis. The AUC for differentiating MPM from metastases was 0.81 for SMRP, 0.61 for CYFRA 21-1, and 0.20 for CEA (p < 0.001). In cases with negative or suspicious cytology, SMRP and CYFRA 21-1 identified 36/71 and 46/66 malignant PEs (29 and 31 MPM, respectively). Only 1 MPM showed a high CEA concentration. No single marker showed the best performance in any comparison. Results suggest that SMRP could improve CYFRA 21-1 and CEA accuracy in the differential diagnosis of MPM.

Expression of bile duct transcription factor HNF1β predicts early tumor recurrence and is a stage-independent prognostic factor in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) frequently exhibits biliary differentiation, which is typically overlooked. Hepatocyte nuclear factor 1β (HNF1β), a bile duct-specific transcription factor expressed in bile ducts but not in the normal hepatocytes, is also expressed in HCC.

MATERIALS AND METHODS

The expression of HNF1β and the biliary differentiation marker cytokeratin 19 (CK19) were retrospectively evaluated using immunohistochemistry in 159 surgically resected primary HCCs.

RESULTS

A significant correlation was observed between HNF1β protein expression and younger age (p = 0.0293), high serum α-fetoprotein levels (p = 6 × 10(-4)), and high tumor grade (p = 0.0255). However, HNF1β expression exhibited no correlation with tumor stage. Patients with HCCs and HNF1β expression were more likely to exhibit early tumor recurrence (ETR; p = 0.0048) and a lower 5-year survival rate (p = 0.0001). A multivariate analysis indicated HNF1β expression as an independent prognostic factor in HCC (p = 0.0048). A combinatorial analysis revealed additive adverse effects of HNF1β when concomitant with CK19 expression and p53 mutation. Furthermore, HNF1β expression can predict poor prognosis in patients with ETR.

CONCLUSION

Our results indicated that HNF1β expression is a crucial predictor of poor prognosis in HCC and is independent of tumor stage. Moreover, concomitant HNF1β and CK19 expressions exhibited additive adverse effects in HCC, confirming that HCC with biliary differentiation has a poor prognosis.

Characterization of cytokeratin 19-positive hepatocyte foci in the regenerating rat liver after 2-AAF/CCl4 injury

Partial hepatectomy or carbon tetrachloride (CCl4) injury, following treatment of rats with 2-acetylaminofluorene (2-AAF) to inhibit proliferation of hepatocytes, induces proliferation of oval cells and possibly their differentiation into nodular foci of hepatocytes when higher doses of 2-AAF are used. Unfortunately, immunohistochemistry in previous studies failed to show oval cell markers in these foci, and thereby to demonstrate the precursor-product relationship between oval cells and hepatocytes. Immunohistochemistry on livers of rats treated with high dose 2-AAF/CCl4 was used. We found 7.6% of the hepatocyte foci were positive for an oval cell marker cytokeratin 19 (CK-19). These foci were positive for alpha-fetoprotein, less positive for carbamoylphosphate synthetase 1, and more positive for laminin in the basement membrane lining. Rarely present transitional foci had weaker expression of CK-19 and discontinuous laminin. Focal hepatocyte differentiation of oval cells was characterized by cell hypertrophy, membranous CK-19, and positive hepatocyte nuclear factor 4 (HNF-4). HNF-4+ small oval cells surrounding CK-19+ foci were frequently seen, suggesting that a paracrine mechanism(s) may be responsible for the enlargement of CK-19+ foci. In conclusions, oval cells appear to differentiate to CK-19+ foci and then to CK-19- foci in the high dose 2-AAF/CCl4 model.

Maturation of in vitro-generated human islets after transplantation in nude mice

The long-term function of human pancreatic islet grafts may depend on the neogenesis of beta cells from epithelial precursors within the grafted tissue. We have developed an in vitro model for human islet neogenesis. In this study, we have investigated the morphological signs of maturation in cultivated human islet buds (CHIBs) before and after transplantation. Clusterin is a molecule associated with beta-cell differentiation in rodents. In adult human islets, clusterin expression was located only in alpha- and PP-cells, but in CHIBs and human fetal islets, it was distributed in all four types of endocrine cells. Some immature endocrine cells in the CHIBs co-expressed insulin and glucagon. After transplantation, CHIBs became mature with one type of hormone per endocrine cell, and clusterin expression became restricted in alpha-cells. Cells co-expressing endocrine markers and cytokeratin 19, as a sign of ductal to endocrine cell transition, were frequently detected in both fresh islets and CHIBs after transplantation. We conclude that clusterin may be involved in the development of islets, and the in vitro-derived islets become mature after transplantation into nude mice. Ductal cell differentiation into endocrine cells may be an important factor in sustaining the long-term function of islet transplants.

Carcinoma initiation via RB tumor suppressor inactivation: a versatile approach to epithelial subtype-dependent cancer initiation in diverse tissues

Carcinomas arise in a complex microenvironment consisting of multiple distinct epithelial lineages surrounded by a variety of stromal cell types. Understanding cancer etiologies requires evaluating the relationship among cell types during disease initiation and through progression. Genetically engineered mouse (GEM) models facilitate the prospective examination of early oncogenic events, which is not possible in humans. Since most solid tumors harbor aberrations in the RB network, we developed an inducible GEM approach for the establishment and assessment of carcinoma initiation in a diverse range of epithelial tissues and subtypes upon inactivation of RB-mediated tumor suppression (RB-TS). The system allows independent assessment of epithelial subtypes that express either cytokeratins (K) 18 or 19. By Cre-dependent expression of a protein that dominantly inactivates RB and functionally redundant proteins p107 and p130, neoplasia could be initiated in either K18 or K19 expressing cells of numerous tissues. By design, because only a single pathway aberration was engineered, carcinomas developed stochastically only after long latency. Hence, this system, which allows for directed cell type-specific carcinoma initiation, facilitates further definition of events that can progress neoplasms to aggressive cancers via engineered, carcinogen-induced and/or spontaneous evolution.

Expression of the novel protein PTPIP51 in rat liver: an immunohistochemical study

Expression of the novel protein tyrosine phosphatase interacting protein 51 (PTPIP51) was investigated on mRNA and protein level in the liver of adult Wistar rats. The presence of PTPIP51 mRNA was detected by Northern blotting. Immunostaining showed expression of PTPIP51 protein in distinct non-parenchymal cells. These cells were identified as Kupffer cells, stellate cells and natural killer cells by detection of cell-specific antigens. Whereas most endothelial cells lining large vessels reacted positive to the PTPIP51 antibody, sinusoidal endothelium showed no detectable amount of PTPIP51. Furthermore, PTPIP51 was also found to be expressed in cells forming the biliary tree. An additional subcellular analysis of the non-parenchymal cells by means of electron microscopy showed the presence of PTPIP51 protein in the cytoplasm and in the nuclei of non-parenchymal cells. Most of the hepatocytes did not show any immuno-detectable amount of PTPIP51, yet, some revealed PTPIP51 protein either in the cytoplasm or in the nucleus.

In Vitro Expression of Cytokeratin 19 in Adipose-Derived Stem Cells Is Induced by Epidermal Growth Factor

BACKGROUND Cytokeratin 19 (CK19) is a typical epithelial marker. In this study, we determined whether epidermal growth factor (EGF) or basic fibroblast growth factor (bFGF) could enhance CK19 expression in adipose-derived stem cells (ADSCs), thereby inducing the differentiation of ADSCs into epithelial-like cells. MATERIAL AND METHODS ADSCs were isolated from perinephric fat, and the expression of CD29, CD90, and CD105 was confirmed. Following isolation, ADSCs were cultured in static medium or medium containing EGF or bFGF. RESULTS Flow cytometry revealed that EGF and bFGF could alter mesenchymal stem cell markers as well as the cell cycle of ADSCs. Western blotting and immunofluorescence revealed that after 14 days, EGF treatment enhanced the expression of CK19 in ADSCs. CONCLUSIONS Our findings offer important insight for the clinical use of ADSCs in the generation of epithelial-like cells in the future.

Comparative assessment of lymph node micrometastasis in cervical, endometrial and vulvar cancer: insights on the real time qRT-PCR approach versus immunohistochemistry, employing dual molecular markers

To address the value of qRT-PCR and IHC in accurately detecting lymph node micrometastasis in gynecological cancer, we performed a systematic approach, using a set of dual molecular tumor-specific markers such as cytokeratin 19 (CK19) and carbonic anhydrase 9 (CA9), in a series of 46 patients (19 with cervical cancer, 18 with endometrial cancer, and 9 with vulvar cancer). A total of 1281 lymph nodes were analyzed and 28 were found positive by histopathology. Following this documentation, 82 lymph nodes, 11 positive and 71 negative, were randomly selected and further analyzed both by IHC and qRT-PCR for CK19 and CA9 expression. All 11 (100%) expressed CK19 by IHC, while only 6 (54.5%) expressed CA9. On the contrary, all the histologically negative for micrometastases lymph nodes were also negative by IHC analysis for both markers. The comparative diagnostic efficacy of the two markers using qRT-PCR, however, disclosed that the analysis of the same aliquots of the 82 lymph nodes led to 100% specificity for the CK19 biomarker, while, in contrast, CA9 failed to recapitulate a similar pattern. These data suggest that qRT-PCR exhibits a better diagnostic accuracy compared to IHC, while CK19 displays a consistent pattern of detection compared to CA9.

Perinodular CK19 loss in hepatocarcinogenesis

Cirrhotic nodules containing hepatocytes are surrounded by perinodular stroma, that consists of an expanded fibrous matrix and epithelial cells with ductular phenotype, the "ductular-reaction". Stromal invasion is a key histopathologic feature used to differentiate premalignant dysplastic nodules from malignant hepatocellular carcinoma (HCC). K19 immunoreactivity in the stromal compartment in cirrhotic explants was examined. Quantitative differences were manifested in three distinct histologically identifiable patterns: "complex" around cirrhotic nodules, "attenuated" around dysplastic nodules, and "absent" around HCC. These findings suggest marked alterations in cellular identity as an underlying mechanism for the reproducible extralesional K19 pattern that parallels progressive stages of intranodular hepatocarcinogenesis. Paracrine signalling is proposed as a link that emphasizes the importance of the epithelial-stromal compartment in malignant progression of HCC in cirrhosis.

An intra-operative RT-LAMP method allows rapid and reliable detection of sentinel lymph node metastasis in breast cancer patients

The rapid determination of metastasis in sentinel lymph nodes (SLNs) of breast cancer patients plays a significant role in the selection of a surgery strategy. Although a previous one-step nucleic acid amplification assay that uses reverse-transcription (RT) loop-mediated isothermal amplification (LAMP) has showed specific advantages over traditional pathological examination, its target marker requires optimisation. In addition to epithelial-specific CK19, the internal control gene PBGD and the breast-specific PIP were included in the new method. After the RT-LAMP primers were designed and verified using a cell line, the performance of our method was evaluated by comparing it with the corresponding result of the Food and Drug Administration approved breast lymph node (BLN) assay and routine pathological examination. One hundred and seventy-four valid SLN samples from 101 patients were collected from five hospitals. The threshold of reaction time for CK19, PIP and PBGD was defined as 16, 20 and 20 min, respectively. Compared with the BLN assay, the concordance rate of our method was 95.4% (166/174). Statistical analysis revealed that the two methods are consistent (kappa = 0.890, P < 0.001). When compared with pathological examination, the performance of our method (sensitivity = 81.3%, specificity = 89.7%, kappa = 0.691, P < 0.001) was similar to that of the BLN assay (sensitivity = 87.5%, specificity = 84.9%, kappa = 0.668, P < 0.001). This result demonstrates the potential usefulness of our method in clinical practice. In conclusion, we preliminarily established an intra-operative diagnostic method that assimilates the merits of previous assays. In contrast with the BLN assay and pathological examination, our method can be completed in 30 min and shows high sensitivity, specificity and consistency, which we consider as promising for clinical application.

Circulating tumor cells and "suspicious objects" evaluated through CellSearch® in metastatic renal cell carcinoma

BACKGROUND

Recent evidence supports the hypothesis that the CellSearch assay, used in the enumeration of circulating tumor cells (CTCs), may underestimate the number of CTCs, especially in tumors, such as renal cell carcinoma, frequently lacking cytokeratin expression. According to the CellSearch guidelines, all objects with no clear cytokeratin staining are defined as "suspicious objects", and are not counted as CTCs. The aim of this study was to investigate the presence of CTCs and "suspicious objects" in 25 patients affected by metastatic renal cell carcinoma (mRCC).

PATIENTS AND METHODS

Twenty-five patients were enrolled in the study, all with a diagnosis of metastatic clear cell RCC. The CellSearch™ system was used to count the CTC in 7.5 mL of whole blood. A further 10 ml blood obtained from each patient was used to isolate CTCs through CELLection™ Dynabeads®. The expression of cytokeratin (CK) 8, 18, 19 and CD44 were evaluated by RT-PCR.

RESULTS

Standard CTCs and suspicious objects were found in 16% and 60% of the patients, respectively. CK-8/18/19 transcripts were found in 15% and CD44 in 68% of the 19 patients with evidence of classical CTC or "suspicious objects" as assessed by Cellsearch.

CONCLUSION

The low number of CTCs detected through CellSearch in renal cell carcinoma may be due to the presence of a CTC population with atypical characteristics and a peculiar gene expression profile, characterized by lack of cytokeratin expression and gain of CD44.

Epigenetic modifications in salivary glands from patients with Sjögren's syndrome affect cytokeratin 19 expression

Sjögren's syndrome (SS) is a chronic autoimmune epithelitis, and several lines of experiments indicate that multifactorial factors contribute to salivary gland epithelial cells (SGEC) dysfunctions including a combination of environmental factors, lymphocytic infiltrations, genetic predispositions as well as epigenetic defects. Such statement is reinforced by the observation that global DNA methylation (5MeCyt) is altered in minor salivary glands from pSS patients and that such defect is associated cytokeratin 19 (KRT19) overexpression. An epigenetic deregulation of the KRT19 gene was further tested by treating the human salivary gland (HSG) cell line with the DNA demethylating agent 5-azacytidin, and with the histone acetylase inhibitor trichostatin A. Blocking DNA methylation, but not histone acetylation, with 5-azacytidin was associated with KRT19 overexpression at both transcriptional and protein level. Next, analysis of the CpG genome-wide methylome array in the KTR19 locus from long term cultured SGEC obtained from 8 pSS patients revealed a more reduced DNA methylation level in those patients with defective global DNA methylation. Altogether, our data, therefore, suggest that alteration of DNA methylation in SGEC may contribute to pSS pathophysiology in part by controlling the expression of KRT19.

Keratin 13 is a more specific marker of conjunctival epithelium than keratin 19

PURPOSE

To evaluate the expression patterns of cytokeratin (K) 12, 13, and 19 in normal epithelium of the human ocular surface to determine whether K13 could be used as a marker for conjunctival epithelium.

METHODS

Total RNA was isolated from the human conjunctiva and central cornea. Those transcripts that had threefolds or higher expression levels in the conjunctiva than the cornea were identified using microarray technique. Expression levels of three known signature genes and of two conjunctival genes, K13 and K19 were confirmed by using quantitative real-time PCR (qRT-PCR). Protein expression of K12, K13, and K19 was confirmed by immunostaining with specific antibodies on histologic sections of human sclerocornea that contained the conjunctiva, limbus, and cornea and on impression cytology (IC) specimens of the cornea and conjunctiva from normal donors. Double staining of K13/K12 and K19/K12 on histologic sections and IC specimens was performed.

RESULTS

There were 337 transcripts that were preferentially expressed in the conjunctiva. K13 and K19 were among the top twenty transcripts in the conjunctiva and this preferential expression pattern of K13 and K19 was confirmed by qRT-PCR. Immunohistochemical studies showed that K13 was expressed at the posterior limbal epithelium and conjunctival epithelium but was totally absent in the cornea. K12 was expressed in the corneal and anterior limbal epithelia except for the basal layer and was absent from the conjunctiva. In contrast, K19 was detected in the corneal, limbal and conjunctival epithelia. Immunostaining of the IC specimens showed K12(+) epithelial cells in the corneal region, K13(+) cells in the conjunctival area, and K19(+) cells in the corneal and conjunctival specimens. Expression of K13 and K12 on the ocular surface was mutually exclusive on both the histologic and IC samples using double immunostaining.

CONCLUSIONS

K13 is more specific to the conjunctival epithelial cells than K19 and potentially could be used as a marker to identify conjunctival epithelial cells in limbal stem cell deficiency.

Comparison of the Diagnostic Value Between Real-Time Reverse Transcription-Polymerase Chain Reaction Assay and Histopathologic Examination in Sentinel Lymph Nodes for Patients With Gastric Carcinoma

OBJECTIVES

Sentinel lymph node (SLN)-based diagnosis in gastric cancers has shown varied sensitivities and false-negative rates in several studies. Application of the reverse transcription-polymerase chain reaction (RT-PCR) in SLN diagnosis has recently been proposed.

METHODS

A total of 155 SLNs from 65 patients with cT1-2, N0 gastric cancer were examined. The histopathologic results were compared with results obtained by real-time RT-PCR for detecting molecular RNA (mRNA) of cytokeratin (CK)19, carcinoembryonic antigen (CEA), and CK20.

RESULTS

The sensitivity and specificity of the multiple marker RT-PCR assay standardized against the results of the postoperative histological examination were 0.778 (95% confidence interval [CI], 0.577-0.914) and 0.781 (95% CI, 0.700-0.850), respectively. In comparison, the sensitivity and specificity of intraoperative diagnosis were 0.819 (95% CI, 0.619-0.937) and 1.000 (95% CI, 0.972-1.000), respectively. The positive predictive value of the multiple-marker RT-PCR assay was 0.355 (95% CI, 0.192-0.546) for predicting non-SLN metastasis, which was lower than that of intraoperative diagnosis (0.813, 95% CI, 0.544-0.960).

CONCLUSIONS

The real-time RT-PCR assay could detect SLN metastasis in gastric cancer. However, the predictive value of the real-time RT-PCR assay was lower than that of precise histopathologic examination and did not outweigh that of our intraoperative SLN diagnosis.

[Comparative study for detecting micrometastases of lymph nodes in patients with lung cancer]

OBJECTIVE

To set up a new method to detect occult micrometastases of lymph nodes in patients with no-small-cell lung cancer (NSCLC).

METHODS

We had detected 195 lymph node samples taken from 25 patients with NSCLC during the operations. Each lymph node sample was divided into two same parts in size. The one half part of lymph node should be examined by conventional histopathologic examination and immunohistochemical (IHC) staining. All the remaining lymph node samples of each patient should be mixed together for the reverse transcriptase-polymerase chain reaction (RT-PCR) if they located in the same region. As long as the presence of metastatic tumor in one lymph node was found by H&E staining, all other lymph node samples in the same region should not be detected by IHC staining or RT-PCR techniques.

RESULTS

Frozen tissue sections of 135 lymph nodes that were staged as free of metastases by conventional histopathologic examination were screened by IHC staining. 31 lymph nodes showed single cell or cells clusters. Of 39 groups mixed regional lymph nodes which were diagnosed to be devoid of metastases by conventional histopathologic examination, 11 groups were found to have positive reactions to cytokeratin 19-mRNA by RT-PCR. There was a correlation between IHC staining and RT-PCR for detection of nodal micrometastases of NSCLC (U = 7.682, P = 0.0001).

CONCLUSION

IHC staining analysis can facilitate the detection of occult micrometastases in lymph nodes of NSCLC, and its assessment of nodal micrometastases can provide a refinement of TNM stage for partial patients with stage I to II. RT-PCR has the same value as IHC staining in detection of lymph nodal micrometastases. RT-PCR technique can reduce expense of the detecting micrometastases in lymph nodes.