['This study was to investigate whether the expression of a disintegrin and metalloproteinase-9 (ADAM9) is correlated with the expression of hepatoma-derived growth factor (HDGF) in surgically resected non-small cell lung cancer (NSCLC), to evaluate the significance of HDGF and ADAM9 as novel molecular staging biomarkers, prognostic biomarkers and predictive biomarkers for postoperative adjuvant chemotherapy in surgically resected stage I NSCLC, to provide essential consistence proof to the possible novel pathway of HDGF-ADAM9 pathway.', 'Sixty-three cases of resected stage I NSCLC with mediastinal N2 lymph node dissection were immunohistochemically analyzed for HDGF and ADAM9 protein expression. Multivariate analysis and survival analysis were conducted.', "HDGF and ADAM9 were observed highly expressed in NSCLC compared with normal control lung tissues (P < 0.05). HDGF high expression cases showed significantly lower survival rate (55.6 vs. 84.7 %, P = 0.009). HDGF high expression was an independent factor of shortened survival time in resected stage I NSCLC (P = 0.015). ADAM9 high expression cases showed significantly lower survival rate (56.9 vs. 88.7 %, P = 0.015). ADAM9 high expression was an independent factor of shortened survival time in resected stage I NSCLC (P = 0.021). Pearson's correlation analysis revealed that ADAM9 expression was correlated positively and significantly with HDGF expression in 63 cases of stage I NSCLC (r = 0.547, P = 0.000)."] Are hDGF and ADAM9 novel molecular staging biomarkers , prognostic biomarkers and predictive biomarkers for adjuvant chemotherapy in surgically resected stage I non-small cell lung cancer?