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A Thor

Publications and source records attributed to A Thor.

At least 37 records · Page 2Linked to original sources
PubMed1992

ERBB2 amplification in breast cancer analyzed by fluorescence in situ hybridization.

We illustrate the use of fluorescence in situ hybridization (FISH) for analysis of ERBB2 oncogene copy number, the level of amplification (here defined as the ratio of ERBB2 copy number to copy number of chromosome 17 centromeres), and the distribution of amplified genes in breast cancer cell lines and uncultured primary breast carcinomas. The relative ERBB2 copy number determined by FISH in 10 breast cancer cell lines correlated strongly with Southern blot results (r = 0.98) when probes for an identical reference locus were used in the two methods. Metaphase analysis of cell lines showed that amplified ERBB2 copies always occurred in intrachromosomal clusters but that the number and chromosomal location of these clusters varied among the cell lines. In interphase nuclei of primary tumors showing ERBB2 amplification (10/44), ERBB2 copies were seen as one to four clusters, also suggesting intrachromosomal localization. Regardless of the average level of amplification, all these tumors contained highly amplified cell subpopulations with at least 25, and sometimes more than 100, ERBB2 copies per cell. Tumors that did not show amplification by FISH (34/44) had an average of one to five ERBB2 copies scattered randomly in the nuclei and completely lacked cells with high copy levels. FISH results on primary tumors were concordant with slot blot results on amplification and with immunohistochemical detection of overexpression. Quantitative analysis of ERBB2 amplification by FISH may improve prognostic assessments based on the pattern of amplification and detection of heavily amplified tumor cell subpopulations.

Breast Neoplasms↗
PubMed1992

The HER2 (c-erbB-2) oncogene is frequently amplified in in situ carcinomas of the breast.

Amplification and overexpression of the HER2 (c-erbB-2) oncogene was assessed in paraffin-embedded specimens from 27 in situ carcinomas of the breast and from 122 stage II breast cancers. Gene amplification detected in these archival tissues by differential polymerase chain reaction (PCR) was found in 48% of in situ carcinomas and in 21% of stage II lesions (chi 2 = 7.62, p less than or equal to 0.01). In addition, the level of gene amplification correlated with the level of HER2 oncoprotein expression as measured by immunohistochemistry for both in situ cancers (p less than or equal to 0.025) and stage II cancers (p less than or equal to 0.0005). This high incidence of HER2 gene amplification with accompanying overexpression in non-invasive breast tumors suggests that perturbations of the HER2 oncogene are among the earliest and most common genetic lesions in human breast cancer.

Breast Neoplasms↗
PubMed1991

Stress response protein (srp-27) determination in primary human breast carcinomas: clinical, histologic, and prognostic correlations.

Expression of an estrogen-regulated protein known as the 27,000-d heat-shock or stress-response protein (srp-27) was evaluated in human breast carcinomas and established breast cancer cell lines. Results obtained by Northern and Western blot analyses and immunohistochemical methods were concordant. Immunohistochemical assessment of srp-27 expression in 300 breast carcinomas (with median patient follow-up of 8 years) was performed. Twenty-six percent of lymph node-negative and 45% of lymph node-positive tumors were overexpressors. Univariate analysis demonstrated significant correlations between srp-27 overexpression and estrogen receptor (ER) content, pS2 protein expression, nodal metastases, advanced T stage, lymphatic/vascular invasion, and a shorter disease-free survival period (but not a shorter overall survival) for the study population as a whole. Regression tree analysis showed that srp-27 expression was an independent prognostic indicator for disease-free survival only in patients with one to three positive lymph nodes. The Cox proportional hazards model confirmed the independent prognostic significance of nodal involvement, T stage, and ER content but failed to recognize srp-27 overexpression as a significant independent parameter predictive of patient outcome in the patient population as a whole. The observed associations between srp-27 overexpression and more aggressive tumors suggest a biologic role for srp-27 in human breast carcinomas.

Blotting, Western↗
PubMed1991

Ras oncogene mutations in benign and malignant thyroid neoplasms.

Current models for tumorigenesis propose that a series of genetic alterations occur during the progression from the normal cell to the malignant phenotype. Mutations in each of the three ras genes (K-ras, H-ras, and N-ras) have been identified in many human neoplasms, including thyroid cancer. In this study we examined genomic DNA from benign and malignant thyroid neoplasms for mutations that are known to activate the ras oncogenes (codons 12, 13, and 61). DNA from frozen surgically excised tissue (n = 8) and from formalin-fixed paraffin-embedded tissue (n = 30) was amplified by the polymerase chain reaction and screened for mutations using oligonucleotide-specific hybridization. No mutations were identified in follicular adenomas (n = 9). In follicular carcinomas, 2 of 14 tumors contained mutations (N-ras 61, Gln to Arg), and both of these patients had bone metastases. One of 15 papillary carcinomas had a ras mutation (H-ras 12, Gly to Ser). In contrast to other studies, we found that ras mutations are relatively uncommon in both benign and malignant thyroid neoplasms. Studies of larger numbers of tumors and comparisons of different patient populations will be required to assess a possible association of mutations in N-ras 61 with clinically aggressive follicular cancer.

Adenocarcinoma↗
PubMed1990

Enhanced tumor binding using immunohistochemical analyses by second generation anti-tumor-associated glycoprotein 72 monoclonal antibodies versus monoclonal antibody B72.3 in human tissue.

Monoclonal antibody (MAb) B72.3 was generated using a membrane-enriched fraction of a human mammary carcinoma biopsy. It has demonstrated reactivity to the majority of human adenocarcinomas including colorectal, gastric, pancreatic, ovarian, endometrial, mammary, and nonsmall cell lung cancer as well as weak or nondetectable reactivity to the majority of normal adult tissues, with the exception of secretory endometrium. Radiolabeled B72.3 has demonstrated MAb localization of carcinoma in approximately 70% of several hundred colorectal and ovarian carcinoma patients. The B72.3-reactive antigen, tumor-associated glycoprotein 72, has been purified from a human colon cancer xenograft and used as an immunogen to generate second generation MAbs. Twenty-eight of these MAbs, designated CC (colon cancer), were shown to be reactive with tumor-associated glycoprotein 72; direct-binding radioimmunoassays, Western blotting, live cell surface binding assays, liquid competition radioimmunoassays, and affinity constant measurements distinguished CC MAbs from each other and from B72.3. Two of these MAbs, CC49 and CC112, were selected for further immunohistochemical characterization. These MAbs were tested here against a spectrum of normal, benign, and malignant human adult tissues using the avidin-biotin-peroxidase technique, and their reactivity was compared with B72.3. Both CC MAbs were more reactive than B72.3 against a range of tumors. Extensive testing with MAbs CC49 and B72.3 using serial tissue sections demonstrated that both MAbs reacted similarly to most normal adult tissues with MAb CC49 reacting stronger to inflammatory colonic tissue. In 35 of 48 (72%) carcinoma biopsies of the gastrointestinal tract, ovary, breast, and lung in which one of the MAbs reacted to at least 20% of the cells, CC49 reacted to a greater percentage of carcinoma cells and/or tumor-associated mucin than B72.3. The reciprocal was observed in only 2% of the carcinomas. This study thus provides evidence that these second generation anti-tumor-associated glycoprotein MAbs may be more efficient than B72.3 in the further study of human carcinoma cell populations and in the diagnostic and therapeutic procedures presently being pursued with MAb B72.3.

Adenocarcinoma↗
PubMed1990

The application of monoclonal antibodies in the cytologic evaluation of tumors.

The focus of this review has been the application of MAbs as adjuncts in the interpretation of cytology specimens. It is evident that most if not all of the MAbs studied thus far are neither completely tumor-specific nor -sensitive; however, when used to address a directed clinical question, they may be "operationally specific." More important, there continues to be no current substitute for the understanding and practice of sound diagnostic cytopathologic principles. Ultimately, the application of MAbs resides in the importance of tumor-associated antigen expression and phenotyping of tumors with therapeutic and prognostic implications.

Antibodies, Monoclonal↗
PubMed1989

Tumor-associated glycoprotein (TAG-72) expression in ulcerative colitis.

Monoclonal antibody (MAb) B72.3 reactive with the high-molecular-weight (Mr greater than 10(6) tumor-associated glycoprotein (TAG)-72 is being increasingly utilized in vivo and in vitro for a variety of purposes in colon cancer patients. Recent evidence has suggested that the TAG-72 antigen expression may be enhanced in inflammatory bowel disease, particularly ulcerative colitis (Thor et al., 1986a: Cancer Res., 46, 3118-3124). We have utilized 117 paraffin-embedded formalin-fixed colonic specimens from 56 ulcerative colitis patients which demonstrate a spectrum of epithelial abnormalities (reactive atypia, dysplasia, and carcinoma) as well as 11 inflammatory controls to evaluate TAG-72 expression. Our selected patient population all had pan-colitis and demonstrated a generally increasing incidence of dysplasia or carcinoma with duration of disease (20% at 0 to 10 years, 50% at 11 to 20 years, 59% at 21 to 30 years, and 100% at more than 31 years). TAG-72 expression was similar in the control and non-dysplastic colonic epithelia, and increased with low- or high-grade dysplasia as well as carcinomatous lesions (mean cellular reactivities 23.7%, 26.5%, 36.7%, 70% and 84.3%, respectively). Epithelium with low-grade dysplasia exhibited a focal perinuclear, superficial crypt staining (when present). High-grade dysplastic epithelium showed pancytoplasmic, pan-cryptic reactivity. Invasive disease showed cytoplasmic as well as extracellular mucin staining. Biopsies from patients with active disease showed significantly more immunoreactive cells for TAG-72 than patients with quiescent disease. For any given biopsy specimen the percentage of cells reactive did not always correlate with the degree of dysplasia. TAG-72 expression in quiescent disease generally increased with duration of disease, in contrast to active disease which showed no correlation between MAb B72.3 staining and duration of disease. The frequent expression of TAG-72 in actively inflamed colonic mucosa (ulcerative colitis and other colitides) may limit the clinical utility of this antigen for detecting colon cancer in ulcerative colitis patients by serological assay or in vivo radiolocalization techniques. The tendency for TAG-72 expression to correlate with disease duration in patients with quiescent disease and to increase with more severe degrees of dysplasia suggests that the expression of this gene product correlates with the dysplasia-to-carcinoma sequence.

Adolescent↗
PubMed1989

Expression of ras oncogene p21 during human fetal development as determined by monoclonal antibodies RAP-5, Y13-259, and DWP.

In this report we describe the expression of the ras proto-oncogene p21 protein in various tissues during normal fetal development. Conventional, formalin fixed and paraffin-embedded sections of normal organs were examined from fetuses ranging 9 to 42 weeks of gestation. Immunohistochemical localization of ras p21 was accomplished using the broadly reactive, mouse monoclonal antibodies RAP-5 and Y13-259. The monoclonal antibody DWP, which is specific for a mutated form of ras p21 having a valine/cysteine at amino acid position 12, was also used. Detectable expression of the p21 protein was seen at different time periods during fetal development depending on the tissue. The expression of ras p21 (as detected by RAP-5 and Y13-259) was noted in a wide range of cell types and tissues; intense immunostaining was noted in epithelial cells of the gastrointestinal tract, exocrine and endocrine pancreas, renal tubules and transitional urotheliem, as well as in other tissues. This immunostaining generally, but not invariably, corresponded with patterns previously reported in benign and/or malignant neoplasms of adult tissues. In most instances ras p21 expression, when present, occurred during periods of rapid growth in given organ systems. However, some actively proliferating fetal tissues such as thymus and spleen, failed to express detectable ras p21 suggesting that factors other than cell cycle may influence its expression. No reactivity with DWP was noted in any of the tissues, suggesting that the mutated forms detected by this monoclonal antibody are not expressed during normal human embryogenesis. These data show that there is regulated expression, and broad distribution of this gene product in normal developing human fetal tissue.

Antibodies, Monoclonal↗
PubMed1989

Immunohistochemical analysis of normal and mutated ras oncogene p21 expression in human pulmonary and pleural neoplasms.

In this study we examined 214 cases of primary human pulmonary neoplasms for the expression of a mutated form of the ras oncogene p21 product, recognized by the monoclonal antibody (MCA) DWP. Adjacent serial sections from these same cases had previously been used to demonstrate the frequency of ras p21 expression using the broadly reactive anti-ras p21 MCA RAP-5. Confirmation of the increased expression of p21 was accomplished using MCA Y13-259. The use of adjacent tissue sections from these cases allows the direct comparison of the expression of the mutated and non-mutated forms of ras p21. If reactivity with DWP would prove to be significantly more restrictive than that of the "pan" ras MCAs, RAP-5 and Y13-259, it would lend support to the possibility that DWP (and similar MCAs which detect other specific mutations) could be used to define subsets of these neoplasms based on their specific ras p21 phenotype. Since one would anticipate that the valine/cysteine substitution at position 12 of the ras p21 would occur at only low frequencies in human tumors, our results with DWP are consistent with this hypothesis. As previously reported, RAP-5 reacted with a high proportion of lung tumors (100/214 or 47%). In this report, we demonstrate the selective expression of the mutation recognized by the MCA DWP in only 5% of these same tumors (13/214), and that the expression of this mutated form is not restricted to any of the conventional histological subclasses of pulmonary neoplasms.

Antibodies, Monoclonal↗
PubMed1989

Multifocal glioblastoma with liver metastases in the absence of surgery. Case report.

A patient with two intracerebral glioblastomas of differing histology with metastases to the liver in the absence of surgery is reported. The gliomatous nature of the lesions was confirmed by staining for glial fibrillary acidic protein. Histological and immunohistochemical evidence suggests that the metastases arose from the more poorly differentiated of the intracerebral tumors. One of the intracerebral tumors had enhanced expression of the ras p21 oncogene as compared to the other tumors and as compared to nonmalignant brain tissue from this patient.

Aged↗
PubMed1989

ras oncogene p21 expression in hepatocellular carcinoma.

Aberrant proto-oncogene expression has been implicated in hepatic cell proliferation, transformation and carcinogenesis using a rat model. To investigate the role of ras p21 product expression in human hepatocellular carcinoma (HCC), we have localized ras p21 in formalin fixed, paraffin-embedded normal and abnormal livers utilizing the avidin-biotin peroxidase method and a monoclonal antibody to ras-gene product p21. A semi-quantitative estimate of p21 expression was performed by serial dilutions of primary antibody. While low dilutions of anti-p21 stained normal hepatocytes, higher dilutions failed to react with normal hepatocytes and these dilutions were used for assessment of p21 enhancement. Increased p21 expression of ras oncogene in HCC occurs in fibrolamellar carcinomas and other better differentiated HCC. Tumor dedifferentiation is associated with an attenuation of p21 expression. Liver adjacent to HCC exhibits p21 enhancement, in contrast to liver surrounding metastatic carcinoma, suggesting increased p21 expression in HCC induction.

Carcinoma, Hepatocellular↗
PubMed1988

Generation and characterization of B72.3 second generation monoclonal antibodies reactive with the tumor-associated glycoprotein 72 antigen.

Monoclonal antibody (MAb) B72.3 was generated using a membrane-enriched fraction of a human mammary carcinoma biopsy. It has demonstrated reactivity to the majority of human adenocarcinomas including colorectal, gastric, pancreatic, ovarian, endometrial, mammary, and non-small cell lung cancer and no or weak reactivity to normal adult tissues, with the exception of secretory endometrium. The B72.3-reactive antigen, termed tumor-associated glycoprotein (TAG)-72, has been purified and used as an immunogen to generate B72.3 second generation MAbs. Since the source of purified TAG-72 was a human colon cancer (CC) xenograft, these MAbs have been given a CC designation. Twenty-eight CC MAbs, all immunoglobulin Gs, have been generated and shown to be reactive with TAG-72 and via both radioimmunoassay and immunohistochemical analyses show differential reactivity to carcinoma versus normal adult tissue biopsies. Nine CC MAbs (CC11, 15, 29, 30, 40, 46, 49, 83, and 92) were selected for further characterization. As a result of analyses using direct-binding radioimmunoassay to a range of human carcinomas, Western blotting, live cell surface binding assays, five liquid competition radioimmunoassays, and Ka measurements, all nine CC MAbs could be distinguished from each other and from B72.3. The Ka of B72.3 was determined to be 2.54 X 10(9) M-1; all the CC MAbs demonstrated higher KaS with MAbs CC92, 49, and 83 having KaS of 14.26, 16.18, and 27.72 X 10(9) M-1, respectively. These studies thus demonstrate that one or more of the anti-TAG-72 CC MAbs may be more efficient than B72.3, or useful in combination with B72.3, toward the further study of human carcinoma cell population and the diagnostic and therapeutic procedures presently utilizing MAb B72.3.

Animals↗
PubMed1988

Comparison of monoclonal antibodies for the detection of occult breast carcinoma metastases in bone marrow.

Twenty percent (n = 6) of Stage III or IV breast cancer patients (n = 30) had bone marrow metastases detected in bilateral bone marrow biopsy/aspiration preparations using standard histologic preparations. Each metastasis was also detected by four separate monoclonal antibodies (MAbs) which recognize breast carcinoma associated antigens (DF3, anti-EMA, HMFG-2, and CAM5.2). These MAbs were then utilized to stain other bone marrow preparations (n = 81) to determine their utility for the detection of micrometastatic breast carcinoma. MAbs HMFG-2, anti-EMA, and DF3 were each strongly reactive with bone marrows containing histologically-evident metastatic breast carcinoma (18/18). These anti-epithelial membrane antigen MAbs, however, were also reactive with rare plasma cells and immature cells (as well as cell clusters) in some of the control bone marrow samples tested, including those from normal patients and patients with hematologic disorders. They also reacted with some of the preparations from patients with leukemia and lymphoma, and with uninvolved marrows from patients with non-epithelial malignancies. The anti-keratin MAb CAM5.2, in contrast, reacted with 83% (15/18) breast cancer metastases and failed to stain any cells in the various categories of control marrow preparations. These data suggested that MAb CAM5.2 might be utilized to immunohistochemically differentiate micrometastatic breast carcinoma from immature myeloid or erythroid elements. Each MAb was then reacted with histologically uninvolved marrow preparations from the remaining 24 of 30 breast cancer patients in an attempt to identify occult breast carcinoma metastases. While MAbs HMFG-2, DF3, and anti-EMA demonstrated reactive cells in some of these marrows, this reactivity was similar to that seen with control preparations. MAb CAM5.2, in contrast, was negative with all specimens. These data suggest that MAb CAM5.2 may be a useful immunologic probe for the detection and confirmation of metastatic breast carcinoma in bone marrow, while more caution must be employed in the interpretation of results obtained using MAbs anti-EMA, DF3, and HMFG-2.

Adolescent↗
PubMed1988

Reactivity of the monoclonal antibody B72.3 with fetal antigen: correlation with expression of TAG-72 in human carcinomas.

The monoclonal antibody (MAb) B72.3 recognizes a mucin-like glycoprotein, TAG-72, which has been detected in a spectrum of human carcinomas, but not in the normal tissue counterparts. Using avidin-biotin-peroxidase complex (ABC) immunohistochemical techniques, MAb B72.3 was reacted with formalin-fixed, paraffin-embedded fetal and pediatric tissue sections to determine the extent of expression of the recognized antigen in these tissues. First trimester fetal tissues failed to express detectable antigen. Gastrointestinal epithelia from 13 to 34 weeks gestation demonstrated the most immunoreactivity with B72.3 although bronchial respiratory epithelium of the lung, transitional epithelium from the kidney, Hassall's corpuscles of the thymus, and gonadal tissues from fetuses of both sexes were also reactive. The TAG-72 antigen was not detected in fetal breast, pancreas, liver, spleen, adrenal, or heart. Expression of the TAG-72 antigen in malignancy appears to correlate well with fetal tissue reactivity with B72.3.

Antibodies, Monoclonal↗
PubMed1988

Differentiation of adenocarcinoma of the lung from mesothelioma. Periodic acid-Schiff, monoclonal antibodies B72.3, and Leu M1.

The immunohistochemical reactivity of 38 mesotheliomas and 44 adeno-carcinomas or large cell carcinomas of the lung with monoclonal antibodies (MAb) B72.3 and Leu M1 was compared with their reactivity with the routine histochemic stains periodic acid-Schiff with diastase digestion (PAS-D) and alcian blue +/- hyaluronidase. Both MAbs reacted selectively with carcinomas when a positive test was set at greater than or equal to 10% reactive tumor cells. However, MAb B72.3 reacted with significantly more of the carcinomas (86%, chi-square test, P less than 0.01) and bound to a greater percentage of tumor cells (47 +/- 28%; mean +/- SD, t-test, P less than 0.001) than Leu M1 (57% and 25 +/- 28%, respectively). The similar reactivities of surgically resected tumor specimens and post mortem tissues with both antibodies confirmed antigen stability and suggested broad clinical utility. PAS-D stained 61% of the carcinomas. Using the markers for carcinomas (PAS-D, B72.3, and Leu M1), the tumors were classified into the correct group in 80 of 82 (98%) cases (95% confidence level: greater than 92% accuracy). The alcian blue stain was useful to confirm a diagnosis of dimorphic or epithelial mesothelioma (48% were positive).

Adenocarcinoma↗
PubMed1987

Enhanced expression of c-Ha-ras p21 in human stomach adenocarcinomas defined by immunoassays using monoclonal antibodies and in situ hybridization.

Using c-Ha-, c-Ki-, and c-N-ras-specific probes in a RNA-RNA hybridization assay we found enhanced expression of c-Ha-ras protooncogene in stomach adenocarcinomas relative to nonneoplastic epithelium, whereas little or no transcription of either c-Ki- or c-N-ras was detected. Enhanced levels of c-Ha-ras RNA expression were detected in all of the adenocarcinomas examined. Hybridization with c-Ha-ras was also detected in nonneoplastic gastric epithelium adjacent to carcinoma, although the labeling was less intense than that of carcinoma cells. More extensive analysis of the c-Ha-ras p21 expression was then carried out in formalin-fixed, paraffin-embedded tissue sections and extracts from surgically resected stomach tissues using monoclonal antibodies (MAbs) RAP-5 and Y13-259. The data obtained from the immunohistochemical studies were consistent with the results of in situ hybridization assay. Adenocarcinomas were much more reactive with MAb RAP-5 than benign and normal tissues, and the majority of carcinomas demonstrated increased expression of c-Ha-ras p21. Quantitative liquid competition radioimmunoassays using MAb Y13-259 also demonstrated significantly higher levels of c-Ha-ras p21 in extracts from stomach adenocarcinomas than those from normal mucosae. No strict correlation was found between ras p21 expression and the degree of tumor differentiation or histological type. Although advanced carcinomas generally demonstrated higher levels of ras p21 than early carcinomas, no correlation among advanced carcinomas and ras p21 levels was observed in relation to depth of tumor invasion to the muscularis propria, subserosa, or serosa. Benign lesions, in comparison, were much less reactive with MAb RAP-5 than carcinomas. Among the benign lesions tested, dysplastic lesions were more reactive than nondysplastic lesions. Normal stomach mucosa was generally nonreactive with the exception of parietal cells. Our results indicate that transformation of the stomach mucosa from benign to malignant phenotype is associated with an increase in c-Ha-ras p21 expression.

Adenocarcinoma↗