Individual analyses of cohort subsets representing the two major histological subtypes, adenocarcinoma and squamous cell carcinoma, revealed that tumor MMP3 expression is more strongly associated with poor survival in patients with lung adenocarcinoma (Figure 4B, N=720, HR=1.45 [95% CI 1.14-1.84], p=0.0021), while no significant association was found in patients with squamous cell carcinoma (Figure 4C, N=524, p=0.35). This evidence concerns the gene MMP3 and adenocarcinoma.