Quantitative real-time PCR analysis of DDR1 and DDR2 expression performed on the 146 NSCLC tumour samples (full data set available as Supplementary Table S1) showed neither DDR1 nor DDR2 were associated with factors such as tumour stage (P=0.38 and P=0.51, respectively), differentiation (P=0.93 and P=0.60, respectively), and age (Spearman's correlation P=0.82 and P=0.48, respectively). This evidence concerns the gene DDR1 and neoplasm.