MMP-2 concentrations were compared in two groups of controls, non-smokers (NSC) and smokers (SC), with three lung cancer subtypes, including adenocarcinoma (ADC), squamous cell carcinoma (SqCC), and other lung neoplasms (OLN), in relation to the MMP-2-735C/T genotype. This evidence concerns the gene MMP2 and squamous cell carcinoma.