Study of the expression of oncogene in human thyroid cells

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Since oncogenes were discovered in carcinoma virus, these oncogenes have been found to exist in not only carcinoma cells but also normal cells in which they seem to be involved in the proliferation and development of cells. Although many studies of oncogenes have been done in rat and pig thyroid cells, there has been no report on oncogenes in human thyroid cells. These studies were, therefore, undertaken to investigate oncogenes in human thyroid cells.Thyroid cells obtained from Graves' thyroid and normal thyroid at neck surgery were cultured and stimulated by TSH or interleukin 1. Total mRNAs were extracted and Northern blot analysis was performed using ^<32>P-v-myc cDNA. The results revealed that c-myc mRNA transcripts were observed and increased by TSH or interleukin 1 in Graves' thyroid cells while c-myc mRNA were not detected in normal thyroid cells, suggesting that Graves' thyroid cells may express cmyc oncogene in response to stimulation of thyroid stimulating antibodies.Rats we … More re fed low iodine diet and and thyroids were removed and total mRNA was extracted. Northern blot analysis was performed similarly, the results revealed that thyroids obtained from rat fed low iodine diet were enlarged and c-myc mRNA transcript clearly increased compared with control, suggesting that c-myc oncogene may involved in the enlargement of thyroid and that endemic goiter in the area back of iodine may be due to this oncogene expression.ErbA, one of oncogene, was found to be T_3 nuclear receptor gene. Peripheral blood mononuclear cells were studied for erbA mRNA in hyperthyroid patients, hypothyroid patients and normal subjects. The results revealed that erbA mRNA transcript clearly increased in hypothyroidism compared with that of normal and hyperthyroidism, suggesting that T_3 nuclear receptors may increase compensating for deficiency of circulating thyroid hormones.Cytokines have been considered to be involved in autoimmune reaction. Interferon gamma, interferon 1 and 6 were found to inhibit thyroid peroxidase (TPO) and thyroglobulin (Tg) gene expression in human thyroid cell in culture system, suggesting that possible cytokines in autoimmune thyroids may expert negative action on thyroid fundion. Less