Comparison of expression levels of S29,18s rRNA and GAPDH genes in lung tumor tissues

Objective To compare the expression levels of the genes encoding small ribosome subunit S29, 18s rRNA and glyceraldehyde 3 phosphate dehydrogenase (GAPDH) in human lung tumor tissues. Methods Northern hybridizations, and analysis of the results using density scanning.Results No changes were shown in expression levels of S29 and 18s rRNA in tumors compared with the normal lung tissues from same patients. The expression in tumors of the GAPDH, however, was markedly up regulated in all of the tumor samples.Conclusion GAPDH should not be used as internal standard for RNA amount calibration in studies on tumor gene expression; and both tissues and cultured cell lines should be taken for experiments the up regulated expression of GAPDH may possibly be a sign of cellular tumorigenesis.