Detection of overexpression of the insulin receptor gene in laryngeal carcinoma cells by means of the differential display method.

Background: The insulin receptor (IR) is an essential protein localized on the surface of almost all cell types. IR belongs to the tyrosine-kinase gro wth factor receptor family. Insulin mediates proliferative responses in a v ariety of tumor cells, however, the role of the IR molecule in carcinogenes is has not yet exactly been established. Methods: Messenger RNA from mucosa l keratinocytes and laryngeal carcinoma cells were transcribed in cDNA usin g reverse transcriptase and amplified by PCR by means of a number of oligon ucleotides. PCR products were analyzed electrophoretically. Results: Compar ing the electrophoretic pattern of both cell types the overexpression of a 127 bp fragment could be detected in laryngeal carcinoma cells in contrast to benign keratinocytes. Cloning and sequencing this fragment exact homolog ous match was found with exon-2 of the IR gene. The overexpression of the I R gene in laryngeal carcinoma cells was confirmed by Northern hybridization . Conclusions: The results show up-regulation of IR-mRNA in laryngeal carci noma cells suggesting that the number of IR is enhanced in these cells. Hen ce it follows, that the overexpression of IR plays a possible role in laryn geal cancer initiation and/or progression.