Biomedical subjects

Christopher Poremba

Publications and source records attributed to Christopher Poremba.

At least 37 records · Page 2Linked to original sources

PubMed2004

Expression profiling of t(12;22) positive clear cell sarcoma of soft tissue cell lines reveals characteristic up-regulation of potential new marker genes including ERBB3.

Clear cell sarcoma of soft tissue (CCSST), also known as malignant melanoma of soft parts, represents a rare lesion of the musculoskeletal system usually affecting adolescents and young adults. CCSST is typified by a chromosomal t(12;22)(q13;q12) translocation resulting in a fusion between the Ewing sarcoma gene (EWSR1) and activating transcription factor 1 (ATF1), of which the activity in nontransformed cells is regulated by cyclic AMP. Our aim was to identify critical differentially expressed genes in CCSST tumor cells in comparison with other solid tumors affecting children and young adults to better understand signaling pathways regulating specific features of the development and progression of this tumor entity. We applied Affymetrix Human Genome U95Av2 oligonucleotide microarrays representing approximately 12,000 genes to generate the expression profiles of the CCSST cell lines GG-62, DTC-1, KAO, MST2, MST3, and Su-CC-S1 in comparison with 8 neuroblastoma, 7 Ewing tumor, and 6 osteosarcoma cell lines. Subsequent hierarchical clustering of microarray data clearly separated all four of the tumor types from each other and identified differentially expressed transcripts, which are characteristically up-regulated in CCSST. Statistical analysis revealed a group of 331 probe sets, representing approximately 300 significant (P < 0.001) differentially regulated genes, which clearly discriminated between the CCSST and other tumor samples. Besides genes that were already known to be highly expressed in CCSST, like S100A11 (S100 protein) or MITF (microphthalmia-associated transcription factor), this group shows an obvious portion of genes that are involved in cyclic AMP response or regulation, in pigmentation processes, or in neuronal structure and signaling. Comparison with other expression profile analyses on neuroectodermal childhood tumors confirms the high robustness of this strategy to characterize tumor entities based on their gene expression. We found the avian erythroblastic leukemia viral oncogene homologue 3 (ERBB3) to be one of the most dramatically up-regulated genes in CCSST. Quantitative real-time PCR and Northern blot analysis verified the mRNA abundance and confirmed the absence of the inhibitory transcript variant of this gene. The protein product of the member of the epidermal growth factor receptor family ERBB3 could be shown to be highly present in all of the CCSST cell lines investigated, as well as in 18 of 20 primary tumor biopsies. In conclusion, our data demonstrate new aspects of the phenotype and the biological behavior of CCSST and reveal ERBB3 to be a useful diagnostic marker.

Blotting, Northern↗

PubMed2004

Graft-versus-host disease after allogeneic hematopoietic stem cell transplantation induces a CD8+ T cell-mediated graft-versus-tumor effect that is independent of the recognition of alloantigenic tumor targets.

Cure of hematologic malignancies after allogeneic hematopoietic stem cell transplantation is partially attributable to immunocellular antitumor reactions termed graft-versus-tumor (GvT) effect. GvT effects are heterogeneous with respect to effector cell populations, target antigens, and their interrelation with graft-versus-host disease (GvHD). In the present study, allogeneic parent-into-F1 murine transplantation models (BALB/c or C57BL/6 --> [C57BL/6 x BALB/c]F1) with different tumors derived from either parental strain were used to evaluate tumor-specific GvT effects. Compared with syngeneic F1-into-F1 controls, significant CD8+ T cell-mediated GvT effects occurred in both allogeneic transplantation models, even in the absence of histoincompatibilities between donor cells and host tumor. Identical genetic background of donor and tumor precluded allorecognition of tumor cells, indicating that tumor-associated antigens (TAAs) were targeted. With allowance made for selective major histocompatibility complex (MHC) disparities between donor cells and normal host tissue, GvHD was identified as a driving force for TAA-specific GvT effects. Adoptive transfer of the effector cells into secondary tumor-bearing recipients confirmed sustained antitumor activity and specificity of the T-cell response. The results provide experimental proof of a donor CD8+ T cell-mediated TAA-specific antitumor response in vivo that is driven by GvHD. It may represent one of the mechanisms contributing to GvT effects observed in allogeneic transplant recipients.

Adoptive Transfer↗

PubMed2004

Endothelin-1-, endothelin-A-, and endothelin-B-receptor expression is correlated with vascular endothelial growth factor expression and angiogenesis in breast cancer.

PURPOSE: Endothelin-1 (ET-1) and its receptors (ET(A)R and ET(B)R), referred to as the endothelin (ET) axis, are overexpressed in breast carcinomas, and influence tumorigenesis and tumor progression by various mechanisms, including angiogenesis. The objective of the study was to clarify if expression of the ET axis participates in angiogenesis of breast carcinoma EXPERIMENTAL DESIGN: We analyzed expression of ET-1, ET(A)R, ET(B)R, and vascular endothelial growth factor (VEGF) immunohistochemically in 600 tissue array specimens from 200 paraffin-embedded breast carcinomas performing tissue microarray technology. Microvessel density (MVD) was determined by counting microvessels (identified by factor VIII) in each core specimen. RESULTS: Moderate or strong immunostaining was observed for ET-1 in 25.4%, for ET(A)R in 43.7%, and for ET(B)R in 22.2% of breast carcinomas. Of all cases, 44.7% showed significant expression of VEGF. MVD varied between different tumor specimens (range, 0-80; median, 17). We observed a statistically significant correlation between MVD and ET expression status with higher MVD in ET-positive tumors. Moreover, expression of VEGF was found more frequently in tumors with overexpression of the ET axis (each P < 0.001). Staining of VEGF was correlated positively with MVD CONCLUSIONS: These results indicate that increased ET-1, ET(A)R, and ET(B)R expression is associated with increased VEGF expression and higher vascularity of breast carcinomas and, thus, could be involved in the regulation of angiogenesis in breast cancer. Our findings provide evidence that the expression pattern of the ET-axis and in particular of ET(A)R may have clinical relevance in future antiangiogenic targeted therapies for breast cancer.

Breast Neoplasms↗

PubMed2004

Detection of apoptotic caspase activation in sera from patients with chronic HCV infection is associated with fibrotic liver injury.

Chronic hepatitis C virus (HCV) infection is characterized by inflammatory liver damage and is associated with a high risk of development of cirrhosis and hepatocellular carcinoma. Although histological examination of liver biopsies is currently the gold standard for the detection of early liver damage, there is a strong need for better noninvasive methods. We recently demonstrated that the proapoptotic activation of caspases is considerably enhanced in histological sections from HCV-infected liver tissue, suggesting an important role of apoptosis in liver damage. Here, we investigated whether caspase activation is detectable also in sera from patients with chronic HCV infection. Using a novel enzyme-linked immunosorbent assay that selectively recognizes a proteolytic neoepitope of the caspase substrate cytokeratin-18, we demonstrate that caspase activity is markedly increased in the sera of HCV patients. Interestingly, while 27% of patients with chronic HCV infection showed normal aminotransferase levels despite inflammatory and fibrotic liver damage, more than 50% of those patients exhibited already elevated serum caspase activity. Moreover, 30% of patients with normal aminotransferase but elevated caspase activity revealed higher stages of fibrosis. In conclusion, compared with conventional surrogate markers such as aminotransferases, detection of caspase activity in serum might be a more sensitive method of detecting early liver injury. Thus, measurement of caspase activity might provide a novel diagnostic tool, especially for patients with normal aminotransferases but otherwise undiagnosed histologically active hepatitis and progressive fibrosis.

Adult↗

PubMed2004

Peripheral primitive neuroectodermal tumor of the stomach in a 14-year-old boy: a case report.

CONCLUSION: Although PNETs are rare malignancies, they should be considered in the differential diagnosis of submucosal gastric tumours in adolescents with clinical alarm symptoms.NET was confirmed by detection of the characteristic EWS/FLI-1 fusion gene, resulting in a reciprocal translocation t(11;22)(q24;q12). Three distinct liver metastases were detected by CT, MRI, and PET. The tumour failed to respond to neoadjuvant polychemotherapy with vincristine, etoposide, doxorubicin, and ifosfamide. Subtotal gastrectomy was performed and, surprisingly, we found diffuse metastatic infiltration of the liver that had not been detected by preoperative staging. Due to the diffuse metastatic disease the young patient's prognosis has to be considered very poor. Because of the tumour's intense expression of CD117 (c-kit), the patient is now treated with the tyrosine kinase inhibitor imatinib (STI571).

Adolescent↗

PubMed2004

Expression of SOCS-1, suppressor of cytokine signalling-1, in human melanoma.

Cytokine resistance is a well-established feature of melanoma cell progression and represents also a major obstacle in immunotherapy of patients with metastatic melanoma. To check whether suppressors of cytokine signalling (SOCS) play a role in cytokine resistance and tumor progression of melanoma, we investigated the expression and regulation of SOCS-1, an established negative regulator of interleukin-6 (IL-6) and interferon (IFN) signalling. In vitro SOCS-1 transcripts were detectable by RT-PCR in 8 out of 8 human melanoma cell lines derived from different tumor stages. Normal human melanocytes also expressed SOCS-1 mRNA in the presence or absence of artificial growth factors. Both IL-6 and alpha-IFN induced rapid and transient SOCS-1 mRNA expression in WM35 and WM9 melanoma cells. At the protein level, SOCS-1 was undetectable in normal human melanocytes whereas uniformly expressed in all tested melanoma cell lines. The aberrant SOCS-1 protein expression in melanoma cells was recapitalized in situ as shown by immunohistochemical analysis. SOCS-1 immunoreactivity was closely related to tumor invasion (Clark level), tumor thickness according to Breslow, and stage of the disease. In contrast, melanocytes in normal skin or melanocytic nevi lacked SOCS-1 protein expression. Our findings show that melanoma cells express a member of the SOCS family, SOCS-1, in vitro and in situ. SOCS-1 is a progression marker of human melanoma and may downregulate biological responses by endogenous and/or therapeutically administered cytokines.

Antineoplastic Agents↗

PubMed2004

Endoscopic retrograde cholangiopancreatography, intraductal ultrasonography, and magnetic resonance cholangiopancreatography in bile duct strictures: a prospective comparison of imaging diagnostics with histopathological correlation.

OBJECTIVES: A variety of imaging techniques are available to diagnose bile duct strictures; the most effective imaging technique, however, has not been established yet. In the present study, we compared the impact of endoscopic retrograde cholangiopancreatography (ERCP), intraductal ultrasonography (IDUS), and magnetic resonance cholangiopancreatography (MRCP) with regard to diagnosing bile duct strictures. METHODS: We prospectively examined 33 patients with jaundice due to bile duct strictures by ERCP plus IDUS and MRCP. The objectives were to assess diagnostic quality of imaging, complete presentation of the bile duct, and differentiation of malignant from benign lesions. Surgical and histopathological correlations, which were used as the gold standard, were available in all cases since all included patients underwent laparotomy. RESULTS: Diagnostic image quality for ERCP was 88% and 76% for MRCP (p > 0.05). Comparing ERCP and MRCP, complete presentation of the biliary tract was achieved in 94% and 82%, respectively (p > 0.05). ERCP and MRCP allowed correct differentiation of malignant from benign lesions in 76% and 58% (p= 0.057), respectively. By supplementing ERCP with IDUS, the accuracy of correct differentiation of malignant from benign lesions increased significantly to 88% (p= 0.0047). CONCLUSIONS: Comparing ERCP with MRCP, we found adequate presentation of bile duct strictures in high imaging quality for both techniques. ERCP supplemented by IDUS gives more reliable and precise information about differentiation of malignant and benign lesions than MRCP alone without additional imaging sequences.

Analysis of Variance↗

PubMed2004

Endothelin-1, Endothelin-A- and Endothelin-B-receptor expression in preinvasive and invasive breast disease.

Endothelin-1 (ET-1) is overexpressed in breast carcinomas and influences via its receptors (ETAR and ETBR) transformation, differentiation and growth processes in the human breast, but little is known about the ET expression in breast cancer precursors. On this basis we evaluated the expression of ET-1, ETAR and ETBR in a series of breast carcinomas, ductal (DCIS) and lobular carcinoma in situ (LCIS) and normal breast tissue by immunohistochemical (IH) methods. IH staining of ET-1, ETAR and ETBR was performed in 88 invasive breast carcinomas, with adjacent carcinoma in situ and concomitant normal breast tissue. Moderate or strong cytoplasmic immunostaining was observed for ET-1 in 33.3%, for ETAR in 45.3% and for ETBR in 55.7% of invasive breast carcinomas. Comparative analysis of invasive cancer (CA), concomitant carcinoma in situ (CIS) and normal breast epithelium (NBE) revealed a stepwise increase of ET-1 and ETAR expression in the sequence NBE < CIS < CA. ETBR expression tended to be slightly higher in CIS than in CA (NBE versus CIS and NBE versus CA, for ETAR and ETBR, p<0.001, respectively; NBE versus CA for ET-1, p=0.035). Our data suggest that the expression of ET-1, ETAR and ETBR correlates with the acquisition of malignant potential and may be used as a prognostic indicator of aggressive behaviour and invasive potential of premalignant breast lesions.

Biomarkers, Tumor↗

PubMed2004

Estrogen receptor alpha and beta, progesterone receptor, pS2 and HER-2/neu expression delineate different subgroups in ductal carcinoma in situ of the breast.

Antiestrogen therapy of ductal carcinoma in situ (DCIS) has become a more common option in reducing risk of developing invasive cancer. Previously, estrogen receptor alpha (ER-alpha) was evaluated as the only predictive factor. Immunohistochemical staining was performed for ER-alpha, estrogen receptor ER-beta, progesterone receptor (PR), pS2 and her-2/neu in 59 cases of ductal carcinoma in situ (DCIS). We observed a positive correlation between the expression of ER-alpha (p=0.003), PR (p<0.001) and histopathological grading. Of the DCIS, 61.5% of ER-beta positive (p=0.046) and 35.5% of PR positive samples showed a coexpression with pS2, whereas 72.1% of pS2 negative DCIS were also negative for ER-beta and 92.9% of PR negative DCIS were negative for pS2 (p=0.012). In contrast, 50.0% of her-2/neu negative DCIS expressed ER-beta receptor (p=0.052). We propose that there are subpopulations of DCIS which can be described by distinct endocrine-associated expression patterns.

Adolescent↗

PubMed2003

Selective and nonselective toxicity of TRAIL/Apo2L combined with chemotherapy in human bone tumour cells vs. normal human cells.

Although TRAIL/Apo2L preferably induces apoptosis in tumour cells without toxicity in normal cells, many tumour cell types display TRAIL/Apo2L resistance. Whether TRAIL/Apo2L in combination with chemotherapy may overcome TRAIL/Apo2L resistance while maintaining tumour selectivity remains to be determined. Here, we report that while ActD, DOX and CDDP sensitised both OS and Ewing's tumour cell lines and normal cells (hOBs, synovial cells, fibroblasts) to TRAIL/Apo2L-induced apoptosis, the combination of etoposide (VP16) and TRAIL/Apo2L was selectively active on tumour cells without affecting normal cells. Sensitisation of OS cells and hOBs to TRAIL/Apo2L did not correlate with a compatible change in the gene expression profile of the receptors for TRAIL/Apo2L determined by quantitative real-time RT-PCR. Also, sensitisation of the TRAIL/Apo2L death pathway did not rely entirely on the chemotherapy-induced, caspase-dependent cytotoxicity. Further, chemotherapy did not cause a compatible change in expression levels of proteins such as Bcl-2, Bcl-x(L), Bax, cIAP2, XIAP and survivin. However, ActD, DOX and CDDP downregulated expression of cFLIP in OS cells as well as expression of p21 in normal hOBs. Interestingly, while VP16 also extinguished cFLIP in OS cells, which were sensitised for TRAIL/Apo2L by VP16, VP16 induced cFLIP and enhanced p21 levels in normal hOBs, which remained refractory to VP16 plus TRAIL/Apo2L. Together, our data reveal that TRAIL/Apo2L combined with certain chemotherapeutic drugs is toxic to bone tumour and normal human cells and suggest that cotreatment with TRAIL/Apo2L and VP16 provides an attractive approach for selective killing of tumour cells while leaving unaffected normal cells.

Antineoplastic Agents↗

PubMed2003

Expression of endothelin-1, endothelin-A, and endothelin-B receptor in human breast cancer and correlation with long-term follow-up.

PURPOSE: Endothelin-1 (ET-1) is overexpressed in breast carcinomas and stimulates tumor cell growth in an autocrine and paracrine fashion via its receptors, ET(A)R and ET(B)R. In this study, we evaluated the expression of ET-1 and ET receptors in breast carcinomas and determined its clinical and prognostic significance. EXPERIMENTAL DESIGN: We analyzed expression of ET-1, ET(A)R, and ET(B)R in 176 breast carcinomas using a semiquantitative immunohistochemical approach. Statistical analysis of clinicopathological variables such as pT stage, pN stage, hormone receptor status, Her-2/neu amplification, histological grade, and long-term follow-up data were performed. RESULTS: We observed a moderate to strong cytoplasmic staining for ET-1 in 69 (43.1%), for ET(A)R in 74 (46.5%), and for ET(B)R in 86 (53.4%) cases of primary breast cancer. A correlation was found between increased ET-1 expression and its receptors with several clinicopathological parameters that characterize aggressive types of breast cancer, with the exception of increased ET(A)R and ET(B)R expression with positive estrogen receptor status. Elevated expression of ET-1, ET(A)R, and ET(B)R was more common in breast carcinomas of patients with lower disease-free survival time and overall survival. In addition, a statistically significant correlation was observed between ET(A)R expression and reduced disease-free survival time (P = 0.041). Interestingly, the prognostic impact of ET(A)R expression was shown to be more pronounced in the subgroup of patients with a putative favorable prognosis according to classic prognostic factors. CONCLUSIONS: Therefore, analysis of ET(A)R expression may improve the prediction of relapse and death and facilitate an individually based risk-directed adjuvant therapy in breast cancer patients.

Breast Neoplasms↗

PubMed2003

Analysis of cyclooxygenase-2 expression in human breast cancer: high throughput tissue microarray analysis.

PURPOSE: The objective of this study was to evaluate breast carcinomas for the expression of cyclooxygenase-2 (Cox-2) using a tissue microarray (TMA) and to determine its clinical and prognostic relevance. METHODS: We analyzed Cox-2 expression in 600 samples from 200 breast carcinomas immunohistochemically performing TMA technology and semiquantitative analysis. Results were correlated with various clinicopathological variables and follow-up data. Expression of estrogen receptor, progesterone receptor, Ki-67, and Her-2/neu-oncogene was analyzed and correlated with Cox-2 status. RESULTS: We observed a moderate or strong cytoplasmic staining for Cox-2 in 78 (40.6%) of breast carcinomas. Increased Cox-2 expression corresponded to higher pT stage ( P=0.038), amplification of Her-2/neu ( P=0.032), lymphovascular invasion ( P=0.006), a high MIB-1 labeling index (LI) ( P<0.001), and histological grading ( P=0.013). We also observed an inverse relationship between strong Cox-2 expression and estrogen and progesterone receptor content of tumors ( P=0.037 and P=0.010). However, we could not demonstrate a significant association between Cox-2 staining and overall survival or disease free survival time. CONCLUSIONS: These results suggest that Cox-2 expression is significantly associated with less differentiated and more aggressive breast carcinomas and might therefore be a useful prognostic indicator as well as a target for therapy.

Breast Neoplasms↗

PubMed2003

Expression-patterns of the RNA component (hTR)and the catalytic subunit (hTERT) of human telomerase in nonneoplastic prostate tissue, prostatic intraepithelial neoplasia, and prostate cancer.

BACKGROUND: Telomerase, a ribonucleoprotein, is composed of a RNA component (hTR) and two protein subunits. One of these subunits, the catalytic subunit (human telomerase reverse transcriptase, hTERT), represents a reverse transcriptase. hTERT-expression is closely correlated with telomerase activity. The telomerase is thought to be involved in immortalization process. By adding hexamic repeats to the end of chromosomal DNA, the telomeres, the enzyme is able to stop progresssive telomeric DNA loss that occurs during cell division due to the end replication problem that stops the mitotic clock. METHODS: Expression-patterns of hTR using radioactive in situ hybridization with (35)S-labelled RNA probes were compared with immunhistochemical staining for hTERT in 14 cases of archival paraffin-embedded samples of normal prostatic tissue, high-grade prostatic intraepithelial neoplasia (PIN), prostatic cancer, and one atypical adenomatous hyperplasia (AAH). Beside the expression-patterns each telomerase component was evaluated semiquantitatively. RESULTS: hTERT and hTR can be found in nonneoplstic tissue and are upregulated in premalignant transformated lesions. AAH showed no hTERT-expression and low hTR-expression. There is a heterogenous expression within prostatic carcinomas. CONCLUSIONS: No association was observed between the grade of the tumour differentiation and semiquantitative levels of hTR- or hTERT-expression. Telomerase is of limited value for the diagnostic of malignant or benign lesions in prostate.

Carcinoma↗

PubMed2003

Chromosomal alterations in osteosarcoma cell lines revealed by comparative genomic hybridization and multicolor karyotyping.

We characterized the chromosomal alterations in eight osteosarcoma cell lines (OST, HOS, U-2 OS, ZK-58, MG-63, SJSA-1, Saos-2, and MNNG) by comparative genomic hybridization (CGH); gains and losses of DNA sequences were defined as chromosomal regions with a fluorescence ratio, wherein all of the 95% confidence interval was above 1.25 and below 0.75, respectively. In four of 8 cell lines, multicolor karyotyping (MK) was added. CGH revealed the average number of aberrations per cell line was 20.8 (range: 10-31); the average numbers of gains and losses were 11.1 and 9.6, respectively. The frequent gains were identified on 1p21 approximately q24, 1q25-q31, 7p21, 7q31, 8q23 approximately q24, and 14q21; frequent losses were at 18q21 approximately q22, 18q12, 19p, and 3p12 approximately p14. High-level gains were observed on 8q23 approximately q24, 5p, and 1p21 approximately p22. MK revealed the most common translocations in the four cell lines were t(8;9), t(1;3), t(3;5), t(1;13), t(2;6), t(3; 17), t(1;15), t(10;20), and t(6;20). Chromosomes 1, 3, 8, 9, and 20 were most frequently involved in translocation events. The concordance rate of aberrations in CGH and translocations in MK was 76%. MK was useful to identify the chromosomal alterations and as a supplement to the CGH results in three of four chromosomes.

Bone Neoplasms↗

PubMed2003

Secretory carcinoma of the breast: a distinct variant of invasive ductal carcinoma assessed by comparative genomic hybridization and immunohistochemistry.

Secretory carcinomas (SCA) are distinguished from infiltrating ductal carcinomas (IDC) of the breast by their characteristic histomorphology and more favorable prognosis and by the expression of a chimeric tyrosine kinase that is encoded by the ETV6-NTRK3 fusion gene. On this basis, we evaluated 13 SCAs (12 of them with ETV6-NTRK3 gene fusion) by molecular and immunohistochemical (IHC) methods. DNA was obtained from 8 of 13 microdissected SCAs and was analyzed for genetic alterations (GA) by comparative genomic hybridization (CGH). IHC staining was performed for estrogen receptor (ER), progesterone receptor (PR), HER2/neu, and Ki-67 (MIB1) in all 13 cases. Molecular and immunohistochemical results in SCAs were compared with previous data regarding immunohistochemical and molecular characteristics of IDCs. An average of 2.0 GAs (range: 0 to 6) were detected, including recurrent gains of chromosome 8q (37.5%) and 1q (25%) and losses of 22q (25%). Four of 13 (31%) SCAs were positive for ER, and 2 were positive for PR. The mean MIB1-labeling index was 11.4% (range: <1 to 34%). Her-2/neu protein overexpression was detected in 2 cases, including 1 with strong (score 3+) and 1 with weak HER2/neu expression (score 2+). Fluorescence in situ hybridization analysis of the latter case showed no evidence of HER-2/neu-gene amplification. Compared with previous findings in IDCs, SCAs are characterized by a relatively low number of GAs, a low proliferative rate, infrequent HER2/neu protein overexpression, decreased steroid hormone receptor expression, and expression of ETV6-NTRK3 fusion gene. These results support the hypothesis that SCAs have immunohistochemical and genetic features that distinguish them from IDCs of the usual type.

Adult↗

PubMed2003

Evaluation of host stem cell-derived cardiac myocytes in consecutive biopsies in long-term cardiac transplant patients.

BACKGROUND: Bone marrow-derived stem cells are involved in tissue formation in transplanted organs. In human renal cell transplants, recipient-specific cells have been shown to participate in regeneration of interstitial tissue. In hepatic transplants, hepatocytes with a recipient sex chromosome pattern have been observed. Recruitment of stem cells in repair and regeneration of cardiac myocytes has been demonstrated in experimental ischemia. Recently, cardiac antral myocytes of recipient origin have been shown to populate transplanted hearts in gender-mismatched transplants. METHODS: Using the fluorescence in situ hybridization (FISH) technique we examined serial post-transplant right ventricular biopsies and sections of ventricle (at time of autopsy) of 4 gender-mismatched female-to-male transplanted hearts (graft survival 0.5 to 10 years, mean 5.1 years) for Y chromosomes within cardiac myocytes. RESULTS: We detected recipient-specific sex chromosomal patterns in single rare cardiac myocytes in 1 case in a serial biopsy after 7 years of transplant survival. The other serial biopsies, as well as the final sections at autopsy, showed no recipient pattern chromosomes within the myocytes. In addition, 2 cases demonstrated Y chromosomes in the smooth muscle of intracardiac arteries. CONCLUSION: Development of recipient marrow-derived stem cells into functional myocytes in the ventricle of transplanted hearts is a rare feature. The higher percentage of stem cell population in the cardiac atria may be a feature of tissue repair and/or an early feature of transplant physiology. Similar to other transplant organs, recipient stem cells are involved in tissue neovascularization.

Adult↗

PubMed2003

Clonality and loss of heterozygosity of WT genes are early events in the pathogenesis of nephroblastomas.

Nephrogenic rests (NRs), putative precursor lesions of nephroblastomas (Wilms' tumors), are found in 25% to 40% of kidneys presenting with nephroblastomas. Nephroblastomas are clonal tumors that, according to a genetic multistep model, are thought to arise as subclonal proliferations from NRs by accumulating genetic alterations. Different candidate genes for the pathogenesis of nephroblastomas have been identified, including those at chromosomes 11p13 (WT1 gene), 11p15 (WT2 gene), and 16q (WT3 gene). We investigated clonality and loss of heterozygosity (LOH) at these loci in different subtypes of NR. After microdissection under microscopic control, we analyzed a highly polymorphic locus of the human androgen receptor gene (HUMARA) for nonrandom X-inactivation of genomic DNA using a methylation-sensitive restriction enzyme to investigate clonality. Out of 14 patients, we found that 1 case each of adenomatous and hyperplastic NR and 2 of 7 cases of sclerosing NR were monoclonal. Five patients were noninformative. We assessed LOH at chromosomes 11p13, 11p15, and 16q by analyzing polymorphic gene loci at these regions. One hyperplastic NR and the corresponding tumor showed LOH at 11p13 and 11p15; 1 sclerosing NR and the corresponding tumor exhibited LOH at chromosome 16q. We demonstrate for the first time that sclerosing NRs can exhibit genetic alterations found in nephroblastomas, namely monoclonality and LOH at the WT gene loci. The histological morphology is no different between NRs with these genetic alterations and NRs without them. We conclude that these genetic changes are early events in the multistep genetic pathogenesis of nephroblastomas; however, they do not seem to fully determine a malignant potential of NR.

Child, Preschool↗

PubMed2003

Sacral infiltration in pelvic sarcomas: joint infiltration analysis II.

The incidence and characteristics of sacral infiltration in pelvic sarcomas were analyzed. Fifty-one patients with a pelvic sarcoma (chondrosarcoma, 15 patients; Ewing's sarcoma, 23 patients; and osteosarcoma, 13 patients) abutting the sacroiliac joint had surgical treatment. Tumor infiltration into the sacrum was suspected based on preoperative images in 18 patients; 15 of 18 patients had histologic tumor invasion. There was a significant difference of median volume of sarcomas with and without infiltration. One of 23 Ewing's sarcomas, seven of 15 chondrosarcomas, and seven of 13 osteosarcomas penetrated the sacroiliac joint into the sacrum. Logistic regression test showed that diagnosis was the most important factor influencing sacral infiltration. Twelve tumors infiltrated through the posterior part of the joint, two tumors infiltrated through the anterior part, and one large tumor infiltrated through an unknown route. To obtain wide surgical margins, patients at risk (elderly, large tumor, or diagnosis of osteosarcoma or chondrosarcoma) for sacral involvement may require extended internal hemipelvectomy with the medial margin extending into the sacrum. High quality imaging studies should be used to assess the need for transarticular resection.

Adolescent↗