Key Points
• In the current study, researchers mined the Cancer Genome Atlas (TCGA) for estrogen receptor genes and estrogen signaling pathway genes. They then individually compared the expression of each gene in tumor tissues and adjacent normal tissues for lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC).
• The researchers validated that 6 genes (SHC1, FKBP4, NRAS, PRKCD, KRAS, ADCY9) exhibited different expression between tumor tissues and adjacent normal tissues in the setting of LUAD, whereas 3 genes (FKBP4, KRAS, ADCY9) predicted LUAD outcomes.
• “In this study, FKBP4, ADCY9, and KRAS were differentially expressed in cancer tissues and adjacent normal tissues of LUAD and were related to the prognosis of LUAD. However, no gene was not only differentially expressed in cancer tissues and adjacent normal tissues but also related to prognosis in LUSC,” the authors noted. “Since LUAD and lung squamous cell carcinoma (LUSC) have significantly different clinical characters and outcomes in lung cancer, researchers suggest these two different cancers should be analyzed separately to provide more precise outcomes.”
• One limitation of the study was that the relationship between lung cancer and gene expression was merely correlated and not causal. Furthermore, normal tissue samples in the TCGA database are less numerous than those of lung cancer. Another limitation involved the underlying biological mechanisms of genes heightening lung cancer risk and affecting the survival time of lung cancer patients. Lastly, no vitro experiments were performed to validate the link between the genes and LUAD.