Original Article - Mitochondrial DNA 4977 BP deletion mutations in lung carcinoma

BACKGROUND: The most common and also the most often assayed mtDNA deletion mutation, ΔmtDNA 4977sub has been demonstrated in various types of human cancer. However, knowledge about ΔmtDNA 4977 in lung carcinoma is poor. AIM: To study the 4977 bp deletions of mitochondrial DNA (ΔmtDNA 4977) 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: ΔmtDNA 4977 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 ΔmtDNA 4977 deletions between the tumor and adjacent normal lung tissues ( P value = 0.815). Moreover, no significant difference was found in the frequency of ΔmtDNA 4977 deletions between the tumor and histologically normal lung tissues in subjects without lung cancer ( P value = 0.101). However, the correlation between ΔmtDNA 4977 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 4977 bp deletion, which is not specific to lung cancer, may reflect the environmental and aging process influences operative during tumor progression