Abstract: To understand the role of mitochondrial DNA(mtDNA) in carcinogenesis , Single2step Method was used to isolate the mtDNA f rom human adenocarcinoma cell line SPC - A - 1. The mtDNA was analyzed by rest riction f ragment length polymorphism(RFL P) with 11 kinds of rest riction endonuclease , which were Pvu Ⅱ,Xho Ⅰ,Pst Ⅰ、EcoR Ⅰ,Bst E Ⅱ,Hind Ⅲ,Hpa Ⅰ,Bcl Ⅰ, EcoR Ⅴ,Sca Ⅰand Xba Ⅰ. Rest riction map of mtDNA f rom SPC - A - 1 cell was obtained by the single and double2digestionn method. It was found that any variation at 32 rest riction2sites failed to be detected in the coding region of mtDNA f rom SPC - A - 1 cell line. But a new site was found at nucleotide 16276( EcoRV) within the noncoding region. These result s indicate that the primary st ructure of gene coding region of mtDNA isolated f rom SPC - A - 1 cell is highly conserved. Whicle the major variation of nucleotide is probably located in the noncoding region.

Key words: lung carcnoma, Mitochondrial DNA, RFL P