Nakajima N, et al. - Experts aimed to investigate GATA6 expression in lung adenocarcinomas (LAs) by immunohistochemistry (IHC) in order to define its relationship with clinicopathological characteristics. With tissue microarray slides containing 348 LAs, IHC analysis of GATA6 was performed. They evaluated the relationship between GATA6 expression and clinicopathological parameters. In addition, they evaluated GATA6 expression in epithelial tumours other than lung cancer. Results of this study suggested that GATA6 could interact with hepatocyte nuclear factor 4α (HNF4α) and contribute to the development of mucinous-type LAs.