Biomedical subjects

J K Field

Publications and source records attributed to J K Field.

120 records · Page 7Linked to original sources

PubMedDate not supplied

Ras, C-myc and C-erbB-2 oncoprotein expression in non-AIDS Mediterranean Kaposi's sarcoma.

We have studied ras p21, c-myc p62 and c-erbB-2 oncogene expression in fourteen Greek patients with NON AIDS Mediterranean Kaposi's sarcoma using immunohistochemical analysis. Elevated expression of ras p21 expression was observed in all 14 cases studied (8 of which had intense levels of staining), whereas expression of c-myc and c-erbB-2 was less frequent, (6 out of 13 cases tested showed elevated c-myc expression and 6 out of 13 showed elevated c-erbB-2 expression). This report indicates that aberrant ras p21 oncogene expression is a feature of Kaposi's sarcoma and may be important in the early stages of this disease.

Acquired Immunodeficiency Syndrome↗

PubMedDate not supplied

Immunocytochemical study of RAS oncoprotein in cytologic specimens of primary lung tumours.

We have examined the distribution of ras p21 oncoprotein expression in cytologic specimens from 73 primary bronchial carcinomas using an immunocytochemical analysis. The cytologic preparations studied represent the two major groups of histological types of lung cancer: Small Cell Lung Carcinoma (SCLC) and Non-Small Cell Lung Carcinoma (NSCLC) (squamous cell carcinoma and adenocarcinoma). The differential expression of ras p21 oncoprotein correlated with histological classification and was found in 30% of 23 small cell lesions, 61% of 28 squamous cell lung carcinomas and 32% of 22 adenocarcinomas. The ras p21 oncoprotein was commonly expressed in NSCLC cases (48%) as compared to SCLC cases (30%).

Adenocarcinoma↗

PubMedDate not supplied

c-myc oncoprotein in bronchial carcinoma: expression in all major morphological types.

We have studied the prevalence of a 62 kd protein product of the c-myc oncogene in tissue biopsies from 79 primary bronchial carcinomata using the monoclonal antibody Myc 1-9E10 and the avidin-biotin complex (ABC) technique. This oncoprotein was strongly expressed in 43% of 37 squamous lesions, 29% of 14 adenocarcinomata, 42% of 7 non-small cell lesions not further classifiable and 19% of 21 small cell neoplasms, all of classical morphology. There was no statistical difference between groups in the prevalence of its expression, nor was it related to survival. This oncoprotein is commonly expressed in non-small cell as well as small cell bronchial carcinomata and, in the latter, is not confined to those variant tumours which possess a "large cell" morphology and carry a poor prognosis.

Adenocarcinoma↗

PubMedDate not supplied

Expression of ras p21 and myc p62 oncoproteins in small cell and non small cell carcinoma of the lung.

Ras p21 and myc p62 expression has been examined immunohistochemically in seventy specimens of bronchial carcinomas. Both ras and myc oncoproteins were found to be overexpressed at a higher frequency in non small cell carcinomas (squamous cell carcinomas and adenocarcinomas) compared to the small cell carcinoma specimens; however only myc p62 overexpression was found to be statistically significant. Also, ras p21 oncoprotein expression was frequently overexpressed in adenocarcinomas compared to squamous cell carcinomas (p less than 0.05). Overexpression of c-myc p62 was found to correlate with poorly differentiated squamous cell carcinomas compared to the well and moderately differentiated tumors. The results of this study indicate that both the ras and myc oncogenes are important in the progression of bronchial carcinomas.

Adenocarcinoma↗

PubMedDate not supplied

The role of ras and myc oncogenes in human solid tumours and their relevance in diagnosis and prognosis (review).

Advances in the field of oncogenes have produced a tool to investigate the different stages in multistep carcinogenesis. The role of the ras and myc gene families have been extensively investigated in the progression of carcinogenesis in a range of human solid tumours. This review critically analyses the data available on the role of these oncogenes in the six most common cancers worldwide, (i.e. cancer of the stomach, lung, breast, colon, cervix, and mouth and pharynx). In certain cases the incidence of aberrant gene expression and genetic alterations of the ras and myc gene families have been shown to be important in the progression of these cancers and may be of use as prognostic indicators.

Breast Neoplasms↗

PubMedDate not supplied

Evaluation of the ras and myc oncoproteins in benign gastric lesions.

Ras and c-myc oncoprotein expression was analyzed using specific monoclonal antibodies Y13-259 (for ras p21) and mycl-9E10 (for c-myc p62) in 144 histological sections derived from benign gastric lesions. Increased expression of ras p21 was observed in inflammatory metaplastic, dysplastic, hyperplastic and cystic histological changes, and on the basis of ras p21 staining three distinct histological groups emerged: (i) cystic changes, hyperplastic polyps; (ii) inflammatory gastritis; (iii) metaplastic, dysplastic and adenomatous polyps. Elevated levels of ras p21 expression were found at significantly higher levels than those of c-myc expression in dysplastic lesions. However the expression of the c-myc oncoprotein was less frequent than ras p21 in all other histological types. With the exception of parietal cells, normal stomach mucosa was found to express low levels of both ras p21 and c-myc oncoproteins.

Antibodies, Monoclonal↗

PubMedDate not supplied

ras, c-myc and c-erbB-2 oncoproteins in human breast cancer.

The expression of ras, c-myc and c-erbB-2 oncoproteins in 100 human (73 ductal and 27 lobular) breast carcinomas has been examined using an immunohistochemical analysis. The monoclonal antibody Y13 259 has been used for the ras p21, the monoclonal antibody Myc1-9E10 for the c-myc p62 and the polyclonal antibody pAb1 (from Triton Bioscience Inc.) for the c-erbB-2 p185 oncoproteins. The following conclusions can be drawn from the analysis: Of the 100 breast carcinoma cases studied only 14 did not express any of the three oncogenes. The remaining 86 were positive for one or more of the three oncoproteins. Ductal carcinomas expressed oncoproteins in 92% of the cases (67/73), whereas lobular carcinomas expressed them in 70% of the cases (19/27). The most frequently expressed was c-myc p62 in 70% of cases followed by ras p21, 55% and c-erbB-2, 35%. Elevated expression of ras, myc or erbB-2 oncogenes did not correlate with the presence of metastasis in auxiliary lymph nodes, the numbers of infiltrated lymph nodes the grade of the tumor or hormone status. However, there appears to be a correlation between increased ras staining intensity and patient's age, below 50 years.

Adult↗

PubMedDate not supplied

Multiple transcriptional activation of cellular oncogenes in human head and neck solid tumours.

Expression of six cellular oncogenes in fresh human tumours and normal tissue from head and neck regions of 20 patients were assessed: 7 samples of normal tissue (controls), 4 premalignant (pleomorphic salivary adenoma) and 14 malignant tumours (squamous cell carcinoma) were examined. Normal and malignant tissue was available from the same patient in four cases, whereas normal and premalignant tissue in one case. Significant elevation of Ha-ras, Ki-ras, and myc oncogene expression were found both in premalignant and malignant tumours as compared to the normal tissue. Oncogenes fes, abl, and sis were expressed at similar low levels in all tissues examined. The results suggest activation of multiple oncogenes in premalignant and malignant tumours from the human head and neck regions.

Adenoma↗

PubMedDate not supplied

High levels of c-myc protein in human breast tumours determined by a sensitive ELISA technique.

We have previously examined the expression of (H-ras) oncogene related transcripts (Spandidos and Agnantis: Anticancer Res 4: 269-272, 1984) and also the activation of the H-ras oncogene (Spandidos: Anticancer Res 7: 991-996, 1987) in human malignant breast cancers. Our results revealed overexpression of the H-ras transcripts in malignant compared to normal tissues, while in the same tumour specimens certain point mutations and other genetic changes have been found in the H-ras gene. In this paper we have investigated c-myc oncoprotein expression in the same tumour samples using an ELISA technique (Moore et al: Oncogene Res 2: 65-80, 1989). Elevated c-myc oncoprotein expression was found in all of the tumour specimens compared with normal breast tissues from a patient with no evidence of the disease. A correlation was found between T stage and c-myc expression in both the normal tissue from the resection margin and in the breast tumour specimens. However, no correlation was found between survival and elevated c-myc expression.

Adult↗

PubMedDate not supplied

Clinical relevance of oncogene expression in head and neck tumours.

A study was undertaken to determine whether the variation in the increased expression of three oncogenes (Ha-ras, Ki-ras and myc) could be correlated with various clinicopathological parameters of squamous cell carcinoma (SCC) of the head and neck region. No correlation was found with sex, age, site of primary tumour, level of differentiation of the tumour, previous X-ray treatment, or fate. The one exception was myc expression with TNM staging of SCC. A significant increase was found for myc expression in TNM Stage III and IV as compared to the combined stages of I and II. Elevated expression of Ha-ras, Ki-ras and myc oncogenes was found in pleomorphic salivary adenoma (PSA), but at a lower level than SCC. It is proposed that in a percentage of cases the elevated expression of these oncogenes in PSA corresponds to a relatively early event in the multistep process of carcinogenesis.

Adenoma, Pleomorphic↗

PubMedDate not supplied

Detection of the tumour suppressor gene p53 in nasopharyngeal carcinoma in Hong Kong Chinese.

This study has investigated the expression of the p53 tumour suppressor gene in 41 cases of primary nasopharyngeal carcinomas (NPC) using the p53 monoclonal antibody BP53-12. Moderate p53 expression was found in 54% and strong expression in 12% of the specimens. There was no correlation between p53 expression and any of the clinicopathological parameters or survival. Surprisingly, three research groups have investigated p53 mutations in NPC and found no fresh tumour specimens to contain p53 mutations in exons 4-8 of the gene. It may be argued that as p53 overexpression has been demonstrated in 70% of the patients investigated in this study, that the mutations lie outside the 4-9 exon region. We are in the process of testing this hypothesis.

Adult↗

PubMedDate not supplied

Genomic instability in squamous cell carcinoma of the head and neck.

The role of genomic instability in the development of squamous cell carcinoma (SCCHN) has become apparent with the publication of three major allelotype analysis of this disease, as well as many publications which have concentrated on specific target regions. The measurement of accumulated genetic alterations or fractional allele loss, as determined by allelotype analysis, provides a useful molecular indicator of tumour behaviour. In one major study, a positive correlation was found between FAL > median value and lymph node metastasis and also with a poor clinical outcome. In addition the recognition of microsatellite instability as a marker of DNA repair defects has provided a further molecular marker of the disease process and that loss of heterozygosity analysis and microsatellite instability appear to be independent genetic events in the development of SCCHN. Furthermore, the recognition of a number of novel target regions in SCCHN on chromosome arms, 1 p, 3p, 8p, 9p, 13q, 17p and 18q and our understanding of the role of certain oncogenes and tumour suppressor genes and their interaction with human papillomavirus has provided further elucidation of the neoplastic process. Even though this review describes a number of molecular events in SCCHN, the sequence of events still eludes the scientific community at present.

Alleles↗