Quantitative detection of common deletion of mitochondrial DNA in hepatocellular carcinoma and hepatocellular nodular hyperplasia

Figure 1 Human mitochondrial DNA showing the 4997-bp deletion. The genes disrupted by the 4997 bp deletion between nucleotide positions 8469 and 13447 encode four polypeptides for complex I (ND3, ND4, ND4L and ND5), one for complex IV (CO III) and two for complex V (ATP8 and ATP6), and five tRNA genes for the amino acids G, R, H, S and L. CD represent the PCR primers position that flank the common deletion region.

Figure 2 Detection results of CD-mtDNA in HCC. A: Conven-tional PCR results: Lane M, marker, Lane 1, negative control, Lane 2, positive control, Lane 3-4, nasopharygitis samples, and Lane 5-8, NPC samples; B: Real-time PCR result shows the amplification plot of fluorescence intensity against the PCR cycle. Each plot corresponds to a HCC sample. The X axis denotes the cycle number of a quantitative PCR reaction. The Y axis denotes the Rn, which is the fluorescence intensity over the background. The correlation coefficient is 0.994.

Figure 3 Sequencing result of the amplified CD-mtDNA from HCC. Comparison with the MITOMAP Human mtDNA Cambridge Sequence data (http://www.mitomap.org), the deletion region (red bar region) is a 4981 bp deletion from position 8470 to 13450 of the mtDNA.

Figure 4 Correlations of CD-mtDNA with HCC and HNH. The CD-mtDNA rate in HCC and HNH lesions was signifi-cantly higher than that in paired noncancerous tissues; the CD/WT-mtDNA ratio in HCC was significant higher than that in paired noncancerous liver tissues (P = 0.02), and was about 25 times that in HNH lesions (P = 0.02).