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Biomedical subjects

M E Sobel

Publications and source records attributed to M E Sobel.

At least 19 recordsLinked to original sources
PubMed2000

Utilization of human tissue in breast cancer research.

The use of human tissue, and material derived from such tissue, for research purposes is currently the subject of much debate. This debate needs to address several issues, including: the principle of abandonment; the distinction between identified and unidentified specimens; general versus specific informed consent; and, with the improvement in biotechnology and medical informatics, the design and security of research databases. The outcome of this debate will shape the way in which research studies using human biological materials are designed and executed.

Breast Neoplasms↗
PubMed2000

Loss of heterozygosity in P53, BRCA1, and estrogen receptor genes and correlation to expression of p53 protein in ovarian epithelial tumors of different cell types and biological behavior.

Loss of heterozygosity (LOH) of tumor suppressor genes (TSGs) in ovarian epithelial tumors of differing cell types and biological behavior has not been thoroughly investigated. Moreover, there have been conflicting reports correlating LOH of the p53 gene to overexpression of p53 protein. This study evaluated 34 formalin-fixed, paraffin-embedded ovarian epithelial tumors for LOH by polymerase chain reaction (PCR) for the following microsatellite markers: TP53(17p13.1/p53 gene), D17S579(17q/BRCA1 gene), and ESR (6q24-27/estrogen receptor gene). LOH of the TP53 marker was detected in 4 (44%) of 9 informative serous cystadenocarcinomas (SCa) but in 0 of 4 informative clear cell carcinomas (CCa) and 0 of 5 informative serous tumors of low malignant potential (SLMP). LOH of the BRCA1 marker was detected in 5 (83%) of 6 informative SCa, but in 1 (13%) of 8 informative CCa and 1 (14%) of 7 informative SLMP. LOH of the ESR marker was detected in 4 (50%) of 8 informative SCa, but in 0 of 4 informative CCa and 1 (16%) of 6 informative SLMP. p53 protein overexpression was present in 8 of 12 SCa but did not correlate to TP53 LOH. LOH for TP53, D17S579/ BRCA1, and ESR is common in ovarian SCa, and is observed in primary tumors as well as metastases. In contrast, these genetic alterations are less common in CCa and in the biologically less aggressive SLMP tumors. These data suggest different mechanisms of oncogenesis in ovarian epithelial tumors of different cell types and biological behavior.

Adenocarcinoma, Clear Cell↗
PubMed2000

Alveolar soft part sarcoma: the role of prognostic markers.

Alveolar soft part sarcoma (ASPS) is a rare malignant neoplasm characterized by slow growth and indolent behavior. The role of proliferative markers and tumor suppressor genes is unknown in these tumors. To investigate their potential role in diagnosis and prognosis, we studied 13 cases of primary ASPS and 14 metastases and correlated them with clinicopathologic parameters. Immunohistochemistry was performed with anti-p53 and anti-Ki-67 antibodies. Polymerase chain reaction after tumor microdissection was performed to search for possible loss of heterozygosity in chromosomes 1p, 9p, 17q, 22q, and TP53 to identify possible changes that may clarify the histogenesis of these tumors. Four of five (80%) primary ASPS cases were positive for Ki-67 and all of them developed later metastases. One patient whose tumor did not stain for Ki-67 remained free of disease for 9 years. Eleven of 13 (85%) metastases were positive for Ki-67; however, there was no correlation with final outcome. All the primary ASPS cases analyzed for p53 yielded negative results, but two (15%) of 13 metastases were weakly positive. There was no correlation of these markers with prognosis or clinicopathologic parameters. No loss of heterozygosity was found except in one of nine (11%) informative metastases for D1S165 (at 1p36). Our preliminary data suggest that Ki-67-positive immunostaining may be a prognostic indicator for the development of metastases in ASPS.

Adolescent↗
PubMed1999

The Tall cell variant of papillary carcinoma of the thyroid: cytologic features and loss of heterozygosity of metastatic and/or recurrent neoplasms and primary neoplasms.

BACKGROUND: The Tall cell variant of papillary carcinoma of the thyroid (TCV) is characterized by the proliferation of oxyphilic, tall, columnar cells with a height-to-width ratio of at least 2:1. TCV exhibits more aggressive clinical behavior than conventional thyroid papillary carcinoma (CPC). Cytologic features suggestive of TCV have been described in fine-needle aspiration material from primary tumors. Similarly, loss of heterozygosity (LOH) for chromosome 1 (D1S243) and the p53 gene (TP53) have been reported in TCV but not in CPC, thus making exploitation of this genetic feature a potential tool for molecular discrimination between these two neoplasms. METHODS: Cytology samples of metastatic and/or recurrent neoplasms (M/R) (12 cases) and 7 cases of primary TCV obtained from 12 patients were evaluated. The cytologic findings of these cases were compared with previously published findings. Microdissection and polymerase chain reaction for LOH for chromosome 1 and p53 (D1S243 and TP53 markers) were performed on cytologic smears from 6 cases of M/R tumors and 3 cases of primary tumors. RESULTS: More then 50% of M/R showed atypical follicular cells with enlarged nuclei, granular chromatin, nuclear grooves, pseudoinclusions, and abundant finely granular cytoplasm. Cells were disposed in monolayers (58%) and papillary clusters (50%). Similar findings were present in cases of primary TCV. LOH studies showed that 4 of 6 M/R were noninformative and 2 of 3 cases of primary TCV were informative for the D1S243 marker; however, in contrast with previously published reports, no LOH was detected for the markers evaluated. CONCLUSIONS: M/R and primary TCV have similar cytologic features. Additional studies of larger series of M/R and primary TCV should be performed to delineate further any potential application of LOH for chromosome 1 and the p53 gene as a tool for diagnosing TCV with cytologic preparations. Cancer (Cancer Cytopathol)

Adult↗
PubMed1999

LOH at the APC/MCC gene (5Q21) is frequent in early stages of non-small cell lung cancer.

Lung cancer is the leading cause of death in both women and men in the United States and many European countries. Molecular cytogenetic and LOH analyses of non-small cell lung cancer have shown somatic genetic alterations in a variety of chromosomes, such as 1p, 3p, 5q, 8p, 9p, 11p, 11q and 17p. Allelic deletions of the known tumor suppressor gene APC at 5q21 are frequently observed in advanced stages of lung cancer and have been correlated with poor prognosis in previous reports. We investigated 33 cases of NSCL for LOH at 5q21: 22 squamous cell and 11 adenocarcinomas. Normal and tumor cells were microdissected from paraffin embedded tissues and PCR amplification was performed utilising the specific markers D5S299 and D5S346 at 5q21 and PYGM at 11q13, respectively. Clinicopathological data, survival and recurrence rates were obtained in all cases. We detected LOH at 5q21 in 4/9 (44%) informative adenocarcinomas and in 13/16 (81%) informative SCC. LOH was frequent in early stages (12/15 stage I cases) and did not correlate with recurrence or poor survival. Our results show that LOH at 5q21 is more frequent in squamous cell carcinomas than in adenocarcinomas, is frequent in early stages of the disease, and does not have prognostic significance.

Adenocarcinoma↗
PubMed1999

The use of microsatellite instability in the distinction between synchronous endometrial and colonic adenocarcinomas.

The association of endometrial carcinoma with other gynecologic neoplasms, especially ovarian and fallopian tube carcinoma, has been well documented and is usually interpreted as a result of a field defect. Sporadic synchronous primary carcinomas occurring in the endometrium and colon are extremely rare, especially in the absence of the familial genetic abnormalities seen in hereditary nonpolyposis colorectal carcinoma (HNPCC) syndrome, and may present a diagnostic dilemma. Two cases of synchronous adenocarcinomas of the endometrium and colon were studied for genetic abnormalities and differences to test for the presence of two primary tumors. Primary tumors, metastases, and normal tissues were microdissected from formalin-fixed, paraffin-embedded tissues. PCR amplification was performed for microsatellite DNA markers on chromosome 17q and 11q13. The colonic tumors were moderately and poorly differentiated, invasive, nonmucinous adenocarcinomas, whereas one uterine tumor was endometrioid adenocarcinoma and the other was papillary serous carcinoma. Although microsatellite instability, as evidenced by changes in the lengths of the amplified PCR products, was detected at 17q and 11q13 loci in the uterine and colonic neoplasms, the patterns of instability differed between the two primary tumor sites. Moreover, the lymph node metastasis in one colonic tumor had genetic alterations that differed from that of the primary tumor. In both patients, the molecular studies suggested the presence of two synchronous primary tumors. Molecular techniques may assist in distinguishing two separate primaries by determining the contraction and expansion of microsatellite regions in DNA obtained by microdissection from the primary tumors and associated metastases.

Adenocarcinoma↗
PubMed1999

Laminin receptors in differentiated thyroid tumors: restricted expression of the 67-kilodalton laminin receptor in follicular carcinoma cells.

The expression of integrin laminin receptors was investigated in normal thyroid primary cultures; immortalized normal thyroid cells (TAD-2); papillary (NPA), follicular (WRO), and anaplastic (ARO) thyroid tumor cell lines; seven thyroid tumors (four papillary and three follicular carcinomas); and normal thyroid glands. The expression of alpha1beta1, alpha2beta1, alpha3beta1, alpha6beta1, and alpha6beta4 was found in all tumor specimens and in tumor cell lines, whereas normal thyroid cells and TAD-2 cells lacked the expression of alpha6beta4. Despite the presence of several integrin laminin receptors, adhesion of TAD-2, NPA, and ARO cells to immobilized laminin-1 was poor, whereas WRO cells and follicular carcinoma-derived cells displayed a strong adhesion. Indeed, WRO and follicular carcinoma-derived cells showed expression of a nonintegrin laminin receptor, the 67-kDa high affinity laminin receptor (67LR). TAD-2, NPA, and ARO cells as well as nodular goiter, toxic adenoma, follicular adenoma, and papillary carcinoma-derived cells did not express the 67LR. Adhesion of WRO and follicular carcinoma-derived cells to laminin-1 was specifically inhibited by a recombinant polypeptide containing laminin-binding domains of 67LR, demonstrating that this receptor confers to follicular carcinoma cells attachment capacity to laminin. Moreover, tissue specimens from follicular carcinomas expressed the 67LR, whereas follicular adenomas and normal thyroid tissues were negative. In thyroid tumors, integrin receptors, although abundant, participate weakly in adhesion to laminin. The expression in follicular carcinoma cells of a functional, high affinity 67LR together with nonfunctional integrin LM receptors could be responsible for the tendency of follicular carcinoma cells to metastasize by mediating stable contacts with basal membranes.

Adenocarcinoma, Follicular↗
PubMed1999

Recommended policies for uses of human tissue in research, education, and quality control. Ad Hoc Committee on Stored Tissue, College of American Pathologists.

As recipients of tissue and medical specimens, pathologists and other medical specialists regard themselves as stewards of patient tissues and consider it their duty to protect the best interests of both the individual patient and the public. The stewardship of slides, blocks, and other materials includes providing, under appropriate circumstances, patient materials for research, education, and quality control. The decision to provide human tissue for such purposes should be based on the specific (ie, direct patient care) and general (ie, furthering medical knowledge) interests of the patient and of society. The same standards of responsibility should apply to all medical professionals who receive and use specimens. This document proposes specific recommendations whereby both interests can be fostered safely, ethically, and reasonably.

Biological Specimen Banks↗
PubMed1999

Ethical issues in molecular pathology: paradigms in flux.

Recent advances in molecular pathology and molecular genetics have created new concerns about the use of human biologic materials in research. Since researchers now have the ability to extract and amplify DNA from minuscule archived samples, virtually any human tissue sample can potentially become the template for a test that provides information that may relate to the inherited genes of an individual. Researchers using human biologic materials should follow the 3 basic principles that have been defined for all ethical human subjects research: respect for persons, beneficence, and justice. Institutional Review Boards are responsible for providing review of the risks and benefits of research proposals to safeguard the rights and welfare of human subjects. Currently, there is considerable debate concerning the role of informed consent procedures and the Institutional Review Board oversight process in situations when researchers use human biologic materials that have been anonymized or coded. In 1999, the National Bioethics Advisory Commission is expected to make recommendations to President Clinton and the National Science and Technology Council that are expected to clarify the balance between respect for personal autonomy and the societal need to pursue biomedical research to improve the health and welfare of all individuals.

Ethics, Medical↗
PubMed1999

Infiltrating micropapillary carcinoma of the breast.

Infiltrating micropapillary carcinoma of the breast is a recently described and poorly recognized aggressive variant of infiltrating ductal carcinoma for which the clinical significance and role of prognostic markers are not fully described. In 14 cases of infiltrating micropapillary carcinoma, we studied histologic characteristics; immunohistochemical expression of c-erbB-2, p53, and MIB-1; hormonal expression of these tumors; and genetic alterations on the p53 locus. We correlated these results with clinical outcome. Patient ages ranged from 37 to 58 years (mean, 50 yr). Nine patients presented with a palpable tumor, one with an axillary mass. Three patients had abnormal mammograms. Five patients (36%) presented with Stage II disease, eight (57%) with Stage III, and one (7%) with Stage IV. The tumors were a modified Bloom-Richardson Grade II in nine cases (64%) and Grade III in 5 (36%). Mitoses ranged from 1 to 12 per 10 high power fields. Necrosis was uniformly absent. Psammoma bodies were present in 9 cases (64%) and lymphatic invasion in 10 (71%). In all of the cases, c-erbB-2 was identified immunohistochemically, and MIB-I was positive, staining 30 to 60% of the tumor cells. The cells were immunoreactive for p53 in six (75%) of eight cases, and, when present, stained 20 to 50% of the tumor cells. Loss of heterozygosity on locus 17p13.1 (p53) was identified in 4 of 5 informative samples. Molecular and immunohistochemical analyses had an 80% concordance. Follow-up was available in 11 patients, of whom 9 had recurrence in the skin and chest wall (average time of recurrence, 24 mo). Recognition of this distinctive and aggressive variant of infiltrating carcinoma is important because of its unfavorable prognosis and specific pattern of local recurrence. Its aggressive nature is supported by its advanced stage at presentation and expression of unfavorable prognostic markers.

Adult↗
PubMed1998

Molecular cloning of a mutated HOXB7 cDNA encoding a truncated transactivating homeodomain-containing protein.

Homeodomain-containing proteins regulate, as transcription factors, the coordinated expression of genes involved in development, differentiation, and malignant transformation. We report here the molecular cloning of a mutated HOXB7 transcript encoding a truncated homeodomain-containing protein in MCF7 cells. This is a new example of mutation affecting the coding region of a HOX gene. In addition, we detected two HOXB7 transcripts in several breast cell lines and demonstrated that both normal and mutated alleles were expressed at the RNA level in MCF7 cells as well as in a variety of breast tissues and lymphocytes, suggesting that a truncated HOXB7 protein might be expressed in vivo. Using transient co-transfection experiments, we demonstrated that both HOXB7 proteins can activate transcription from a consensus HOX binding sequence in breast cancer cells. Our results provide evidence that HOXB7 protein has transcription factor activity in vivo and that the two last amino acids do not contribute to this property.

Breast Neoplasms↗
PubMed1998

Formation of the 67-kDa laminin receptor by acylation of the precursor.

Even though the involvement of the 67-kDa laminin receptor (67LR) in tumor invasiveness has been clearly demonstrated, its molecular structure remains an open problem, since only a full-length gene encoding a 37-kDa precursor protein (37LRP) has been isolated so far. A pool of recently obtained monoclonal antibodies directed against the recombinant 37LRP molecule was used to investigate the processing that leads to the formation of the 67-kDa molecule. In soluble extracts of A431 human carcinoma cells, these reagents recognize the precursor molecule as well as the mature 67LR and a 120-kDa molecule. The recovery of these proteins was found to be strikingly dependent upon the cell solubilization conditions: the 67LR is soluble in NP-40-lysis buffer whereas the 37LRP is NP-40-insoluble. Inhibition of 67LR formation by cerulenin indicates that acylation is involved in the processing of the receptor. It is likely a palmitoylation process, as indicated by sensitivity of NP-40-soluble extracts to hydroxylamine treatment. Immunoblotting assays performed with a polyclonal serum directed against galectin3 showed that both the 67- and the 120-kDa proteins carry galectin3 epitopes whereas the 37LRP does not. These data suggest that the 67LR is a heterodimer stabilized by strong intramolecular hydrophobic interactions, carried by fatty acids bound to the 37LRP and to a galectin3 cross-reacting molecule.

Acylation↗
PubMed1998

The 67-kDa laminin receptor originated from a ribosomal protein that acquired a dual function during evolution.

The 67-kDa laminin receptor (67LR) is a nonintegrin cell surface receptor that mediates high-affinity interactions between cells and laminin. Overexpression of this protein in tumor cells has been related to tumor invasion and metastasis. Thus far, only a full-length gene encoding a 37-kDa precursor protein (37LRP) has been isolated. The finding that the cDNA for the 37LRP is virtually identical to a cDNA encoding the ribosomal protein p40 has suggested that 37LRP is actually a component of the translational machinery, with no laminin-binding activity. On the other hand, a peptide of 20 amino acids deduced from the sequence of 37LR/p40 was shown to exhibit high laminin-binding activity. The evolutionary relationship between 23 sequences of 37LRP/p40 proteins was analyzed. This phylogenetic analysis indicated that all of the protein sequences derive from orthologous genes and that the 37LRP is indeed a ribosomal protein that acquired the novel function of laminin receptor during evolution. The evolutionary analysis of the sequence identified as the laminin-binding site in the human protein suggested that the acquisition of the laminin-binding capability is linked to the palindromic sequence LMWWML, which appeared during evolution concomitantly with laminin.

Amino Acid Sequence↗
PubMed1997

New insights into the metastasis-associated 67 kD laminin receptor.

The interactions between tumor cells and laminin or other components of the extracellular matrix have been shown to play an important role in tumor invasion and metastasis. These interactions are mediated by different cell surface molecules, including the monomeric 67 kD laminin receptor. This molecule appears to be very peculiar since so, far only a full-length gene encoding a 37 kD precursor protein has been isolated and the mechanism by which the precursor reaches the mature form is not understood. Based on clinical data, which clearly demonstrate the importance of the receptor in tumor progression, studies were conducted to define the structure, expression, and function of this laminin receptor as a step toward developing therapeutic strategies that target this molecule. The data suggest that acylation of the precursor is the key mechanism in maturation of the 67 kD form. The function of the membrane receptor is to stabilize the binding of laminin to cell surface integrins, acting as an integrin-accessory molecule, although homology of the gene encoding the receptor precursor with other genes suggests additional functions. Downregulation of the receptor expression on tumor cells might open new therapeutic approaches to decrease tumor aggressiveness.

Animals↗
PubMed1997

Galectin-3 and laminin expression in neoplastic and non-neoplastic thyroid tissue.

Galectin-3 is a 31 kD beta-galactoside-binding lectin which is expressed by several types of non-neoplastic and neoplastic cells and which may be involved in cell-extracellular matrix interactions. An immunohistochemical study has been made of the expression of galectin-3, as well as its ligand, laminin, in a spectrum of benign and malignant thyroid neoplasms and in some non-neoplastic conditions. Immunohistochemistry with anti-human recombinant galectin-3 antibody showed consistent, intense positivity in the neoplastic cells of 18 cases of papillary carcinoma and less intense staining in the five anaplastic carcinomas studied. In addition, two out of three poorly differentiated carcinomas, three out of six medullary carcinomas, and four out of eight follicular carcinomas had less intense or focal positivity. One case of Hürthle cell carcinoma showed scattered strongly positive cells. Eight follicular adenomas, three hyperplastic nodules, five nodular goitres, and normal thyroid tissue were negative. Galectin-3 mRNA expression was also evaluated in three of the papillary carcinomas, two follicular adenomas, and one hyperplastic nodule with matched normal tissue. Northern blot analysis demonstrated mRNA overexpression in the three cases of papillary carcinomas, whereas normal and benign tissues were negative. Laminin distribution in neoplastic and non-neoplastic tissue varied with architectural patterns but did not correlate with galectin-3 immunohistochemical expression. We conclude that expression of galectin-3 is limited to inflammatory foci in normal and benign thyroid tissue and is a phenotypic feature of malignant thyroid neoplasms, especially papillary carcinomas.

Antigens, Differentiation↗
PubMed1996

Cloning and expression of a new HOXC6 transcript encoding a repressing protein.

Homeodomain-containing proteins are transcription factors that regulate the co-ordinated expression of multiple genes involved in development, differentiation and malignant transformation. In an attempt to characterize expressed homeobox (HOX) genes in breast cancer cells, we cloned two distinct HOXC6 transcripts from an MCF7 cDNA library, Interestingly, one of them represents a new HOXC6 mRNA encoding a homeodomain-containing protein harbouring a unique N-terminal sequence. Moreover we demonstrate that this HOXC6 transcript is less abundant in human breast cancer cells than in non-tumorigenic cell lines, is detected in breast carcinomas and adjacent tissues and is expressed in a variety of human tumours. In addition, transient co-transfection experiments illustrated that both HOXC6 transcripts encode gene products that repress transcription from a HOX binding sequence in MDA-MB231 cells and co-operate with other HOX gene products such as HOXB7 on their target genes. Taken together, our results suggest that HOXC6 proteins might contribute to the breast cell phenotype through co-operative interactions with other HOX-derived proteins and repression of their target genes.

Amino Acid Sequence↗