[Frequent 4 977 bp deletion of mitochondrial DNA in tumor cell lines, solid tumors and precancerous lesions of human stomach]

To clarify the frequency of mtDNA 4 977 bp deletion in tumor cell lines, solid tumors, patient's serum of gastric tumor and to find a easy and exact method to diagnose gastric tumor.Primer-shift PCR method was used in 13 gastric tumor cell lines, 52 cases of gastric fresh tumor tissues matched the adjacent normal tissues, 40 cases of patient's serum of gastric tumor and 40 cases of normal serums for analysis of mtDNA deletion.Frequency of 4 977 bp mtDNA deletion was detected in 12 of 13 (92.3%) tumor cell lines, 38 of 52 (73.1%) cases of solid tumor tissues, 27 of 52 (52%) adjacent normal tissues, 17 of 40 (42.5%) patient's serum and 8 of 40 (20%) normal serums. Further more, in 2 of 10 pairs microdissected specimens, we found this deletion occurred not only in primary tumor but also in intestinal metaplasia comparing with no deletion was found in normal tissues. The frequency of this deletion was statistically significantly higher in the gastric tumor tissues and serums than in the adjacent normal tissues and serums. A good correlation between the deletion and young age of patients was representative in our data.mtDNA 4 977 bp deletion maybe play an important role in the carcinogenesis of human gastric mucous and maybe has happened in the tumor cell malignant transformation. To detect this deletion in patient's serum is a easy and exact method and maybe become a potential tumor marker.