DDR1 and cancer: To study the prognostic value of DDR1 in early stage NSCLC we used Gyorffy’s database15, which includes data from The Cancer Genome Atlas (TCGA, http://cancergenome.nih.gov), Gene Expression Omnibus (GEO, http://www.ncbi.nlm.nih.gov/geo/) and Cancer Biomedical Informatics Grid (caBIG, http://cabig.cancer.gov/).