The heatmap image of messenger RNA (mRNA) expression of REIC/Dkk-3 gene from the UCSC Cancer Genome Browse, which is freely available public database (https://genome-cancer.ucsc.edu/) (we downloaded the data on July 16 2013), showed that REIC/Dkk-3 gene expression was reduced in majority of examined samples of both lung adenocarcinomas and squamous cell carcinomas compared with normal lung tissues (Figure S1). Here, DKK3 is linked to lung adenocarcinoma.