This study investigates the relationship between mRNA and protein expression in lung adenocarcinomas. The researchers analyzed 165 protein spots representing 98 genes in 76 lung adenocarcinomas and nine non-neoplastic lung tissues using two-dimensional polyacrylamide gel electrophoresis and mass spectrometry. They also used oligonucleotide microarrays to determine mRNA levels for the same samples. Only 28 of the 165 protein spots (17%) showed a statistically significant correlation between protein and mRNA expression (r > 0.4425; p < 0.05). The correlation coefficients ranged from −0.467 to 0.442, and they were not related to protein abundance. No significant correlation was found when using the average levels of mRNA or protein across all samples (r = −0.025). Among the 21 genes with significant correlations, five showed significant differences between stage I and stage III lung adenocarcinomas. The study concludes that only a subset of proteins exhibits a significant correlation with mRNA abundance, suggesting that translation and post-translational modifications influence protein expression in lung adenocarcinomas.This study investigates the relationship between mRNA and protein expression in lung adenocarcinomas. The researchers analyzed 165 protein spots representing 98 genes in 76 lung adenocarcinomas and nine non-neoplastic lung tissues using two-dimensional polyacrylamide gel electrophoresis and mass spectrometry. They also used oligonucleotide microarrays to determine mRNA levels for the same samples. Only 28 of the 165 protein spots (17%) showed a statistically significant correlation between protein and mRNA expression (r > 0.4425; p < 0.05). The correlation coefficients ranged from −0.467 to 0.442, and they were not related to protein abundance. No significant correlation was found when using the average levels of mRNA or protein across all samples (r = −0.025). Among the 21 genes with significant correlations, five showed significant differences between stage I and stage III lung adenocarcinomas. The study concludes that only a subset of proteins exhibits a significant correlation with mRNA abundance, suggesting that translation and post-translational modifications influence protein expression in lung adenocarcinomas.