RESUMO
BACKGROUND: The most common and also the most often assayed mtDNA deletion mutation, degrees mtDNA 4,977 sub has been demonstrated in various types of human cancer. However, knowledge about degrees mtDNA 4,977 in lung carcinoma is poor. AIM: To study the 4,977 bp deletions of mitochondrial DNA ( degrees mtDNA 4,977) in lung cancer, adjacent histologically normal and normal lung tissue and its potential roles in the development of cancer. MATERIALS AND METHODS: Thirty-seven matched lung cancer/adjacent histologically normal and 20 histologically normal lung tissue samples in subjects without lung cancer were analyzed by PCR technique. RESULTS: degrees mtDNA 4,977 deletions were detected in 54.1% (20/37) of lung cancers, 59.5% (22/37) of adjacent normal and 30.0% (6/20) of normal lung tissue samples. No significant difference was found in the frequency of degrees mtDNA 4,977 deletions between the tumor and adjacent normal lung tissues (P value = 0.815). Moreover, no significant difference was found in the frequency of degrees mtDNA 4,977 deletions between the tumor and histologically normal lung tissues in subjects without lung cancer (P value=0.101). However, the correlation between degrees mtDNA 4,977 deletion and age and smoking factors was present in our data. STATISTICAL ANALYSIS: Fisher's exact test was used to assess the difference in different groups by the Scientific Package for Social Sciences (SPSS), version 10.0, Statistical analysis software. CONCLUSIONS: Mitochondrial DNA 4,977 bp deletion, which is not specific to lung cancer, may reflect the environmental and aging process influences operative during tumor progression.