This study investigates the relationship between mRNA and protein expression in lung adenocarcinomas. Researchers analyzed 165 protein spots representing 98 genes in 76 lung adenocarcinomas and nine non-neoplastic lung tissues. They used 2D gel electrophoresis and mass spectrometry to identify proteins and oligonucleotide microarrays to measure mRNA levels. The results showed that only 17% (28 protein spots) of the 165 had a statistically significant correlation between mRNA and protein expression (r > 0.2445; p < 0.05). However, the correlation coefficients ranged from -0.467 to 0.442, indicating a wide variation in the relationship between mRNA and protein levels. The study also found that the correlation between mRNA and protein expression was not related to protein abundance. Additionally, when using average values across all samples, there was no significant correlation between mRNA and protein expression. The study also found that some genes showed significant differences in protein/mRNA correlation between stage I and stage III lung adenocarcinomas. These findings suggest that while a subset of proteins is regulated at the transcriptional level, many are regulated by other mechanisms, including post-translational modifications. The study highlights the complexity of protein and mRNA expression in lung adenocarcinomas and the importance of considering individual isoforms and their regulation. The results indicate that the overall protein expression levels in lung adenocarcinomas cannot be predicted from average mRNA levels. This study provides important insights into the regulation of protein and mRNA expression in lung adenocarcinomas and has implications for understanding the molecular mechanisms underlying cancer progression.This study investigates the relationship between mRNA and protein expression in lung adenocarcinomas. Researchers analyzed 165 protein spots representing 98 genes in 76 lung adenocarcinomas and nine non-neoplastic lung tissues. They used 2D gel electrophoresis and mass spectrometry to identify proteins and oligonucleotide microarrays to measure mRNA levels. The results showed that only 17% (28 protein spots) of the 165 had a statistically significant correlation between mRNA and protein expression (r > 0.2445; p < 0.05). However, the correlation coefficients ranged from -0.467 to 0.442, indicating a wide variation in the relationship between mRNA and protein levels. The study also found that the correlation between mRNA and protein expression was not related to protein abundance. Additionally, when using average values across all samples, there was no significant correlation between mRNA and protein expression. The study also found that some genes showed significant differences in protein/mRNA correlation between stage I and stage III lung adenocarcinomas. These findings suggest that while a subset of proteins is regulated at the transcriptional level, many are regulated by other mechanisms, including post-translational modifications. The study highlights the complexity of protein and mRNA expression in lung adenocarcinomas and the importance of considering individual isoforms and their regulation. The results indicate that the overall protein expression levels in lung adenocarcinomas cannot be predicted from average mRNA levels. This study provides important insights into the regulation of protein and mRNA expression in lung adenocarcinomas and has implications for understanding the molecular mechanisms underlying cancer progression.