High KRT8 Expression Independently Predicts Poor Prognosis for Lung Adenocarcinoma Patients

Abstract

Keratin 8 (KRT8), a type II basic intermediate filament (IF) protein, is essential for the development and metastasis of various cancers. In this study, by analyzing RNA-seq data from the Cancer Genome Atlas (TCGA)-lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC), we have determined the expression profile of <i>KRT8</i>, and assessed its prognostic significance and the possible mechanism underlying the dysregulation. Our results showed that <i>KRT8</i> mRNA expression was significantly up-regulated in both LUAD and LUSC tissues compared with normal lung tissues. The high <i>KRT8</i> expression group for LUAD patients significantly reduced overall survival (OS) and recurrence-free survival (RFS). Univariate and multivariate analysis revealed that <i>KRT8</i> expression was an independent prognostic indicator for poor OS and RFS in LUAD patients. However, <i>KRT8</i> expression had no prognostic value in terms of OS and RFS for LUSC. By exploring DNA copy number alterations (CNAs) of the <i>KRT8</i> gene in LUAD, we found that DNA low copy gain (+1 and +2) was associated with elevated <i>KRT8</i> mRNA expression. From the above findings, we have deduced that <i>KRT8</i> is aberrantly expressed in LUAD tissues and that its expression might independently predict poor OS and RFS for LUAD patients, but not for LUSC patients.