Summary 57 primary tumour samples from Indian oral cancer patients with a 5-15 year tobacco chewing habit, were examined for mutational activation in codons 12, 13 and 61 of the H-ras, K-
Summary Study of expression of ras-related oncogenes in human premalignant polyps and malignant tumours of the colorectum, as well as in normal colorectal mucosa, shows a significant elevation in the premalignant and malignant tissues as compared to their respective colorectal mucosa. These results suggest that activation of the ras oncogene family occurs in the development of colorectal tumours and that elevated expression at a premalignant stage may well be critical in the process of carcinogenesis but not in itself sufficient.
The expression of c-myc was studied in 51 malignant lymphomas and in a variety of normal tissues by immunocytochemistry using monoclonal antibodies raised to different synthetic peptides and reacting monospecifically with the c-myc product (p62c-myc). The c-myc product was detected in only a minority of malignant lymphomas principally those containing cells with immunoblastic characteristics, and was predominantly localised to the cytoplasm. In normal lymphoid tissues only plasma cells and histiocytes were found to have immunoreactivity. In non-lymphoid normal tissues, however, the c-myc product was distributed widely. Marked differences in its intracellular distribution were apparent in different tissues. These findings suggest that the relationship of p62c-myc expression to cell division may be more complex than previously suggested by in vitro studies, and raise the possibility that it may have other functions within the cell.
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Summary We have constructed cDNA libraries from the poly(A)+ RNA of normal colonic mucosa and a liver metastasis from a colonic adenocarcinoma. Differential screening of these libraries using 32P-labelled cDNAs transcribed from poly(A)+ RNAs isolated from specimens of four normal colonic mucosae, five adenocarcinomas, and three liver metastases by Grunstein-Hogness and dot-blot hybridisation has identified a number of recombinant cDNA clones homologous to mRNAs that appear to differ significantly in abundance between normal and neoplastic colon and metastases.These cDNA clones, and others identified in the libraries, may be of considerable importance both as diagnostic tools and in defining the phenotypic changes associated with tumour progression and metastasis.
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