We evaluated the occurrence of mutations in P53, K-RAS, COX-2, expression of COX-2 and hTERT and relations among clinicopathological signs. P53 mutations were identified in 34.4% of tumours, the majority of them occurring in SCC (squamous cell carcinoma, 55.6%). K-RAS was mutated in 12.2% of NSCLC tumours, the majority of the mutations being found in ADC (adenocarcinoma, 27.0%). Mutational screening detected three different COX-2 mutations and five different P53 mutations, published for the first time. With RT-PCR we observed that the expression of the tested genes, hTERT and COX-2, was highly significant for ADC (p<0.01) and SCC (p<0.05). Statistical analysis of the combined results revealed significant correlation between expression of COX-2 and hTERT (p<0.001), hTERT expression and staging (p<0.05) and survival (p<0.01). A positive correlation between COX-2 expression and K-RAS mutation (p<0.05) was also observed. This study provides insight into associations between the analysed biomarkers and the clinical-pathological data of the patients.