Mitochondrial gene mutation, but not large-scale deletion, is a feature of colorectal carcinomas with mitochondrial microsatellite instability

Mutation in D-loop region of mitochondrial DNA in gastric cancer and its significance

AIM: To investigate the mutation in D-loop region of mitoc-hondrial DNA in gastric cancer and its influence on the changes of reactive oxygen species (ROS) and cell cycle.

METHODS: The D-loop region was amplified by PCR and sequenced. Reactive oxygen species and cell cycle were detected by flow cytometry in 20 specimens from gastric cancer and adjacent normal tissues. According to the sequence results, gastric cancer tissue was divided into mutation group and control group. Reactive oxygen species, apoptosis and proliferation in the two groups were compared.

RESULTS: Among the 20 gastric cancer specimens, 18 mutations were identified in 7 patients, the mutation rate being 35%. There were four microsatellite instabilities in the mutations. No mutation was found in the adjacent tissues. Reactive oxygen species, apoptosis, and proliferation in the mutation group were all significantly higher than those in control group.

CONCLUSION: Mutation in D-loop region plays a role in the genesis and development of gastric cancer.

Mitochondrial microsatellite instability in gastric cancer and its precancerous lesions

AIM: To evaluate the role of mitochondrial microsatellite instability (mtMSI) in gastric carcinogenesis.

METHODS: MtMSI was measured with PCR-single strand conformation polymophism (PCR-SSCP) in 68 cases of advanced gastric cancer, 40 cases of chronic gastritis, 30 cases of intestinal metaplasia and 20 cases of dysplasia.

RESULTS: MtMSI was observed in 12.5% (5 of 40) of chronic gastritis, 20.0% (6 of 30) of intestinal metaplasia, 25.0% (5 of 20) of dysplasia and 38.2% (26 of 68) of gastric cancer. These findings showed a sequential accumulation of mtMSI in the histological progression from chonic gastritis to gastric cancer. An association of mtMSI with intestinal histological type and distal location was found (P = 0.001 and P = 0.002), whereas no significant correlation was found between mtMSI and age at diagnosis, sex, tumor size, depth of invasion, lymph node spread and clinical stages (P > 0.05).

CONCLUSION: MtMSI may play an early and important role in the gastric carcinogenesis pathway, especially in the intestinal type and distal gastric cancer.

Nuclear and mitochondrial DNA microsatellite instability in Chinese hepatocellular carcinoma

AIM: To study the nuclear microsatellite instability (nMSI) at BAT26 and mitochondral microsalellite instability (mtMSI) in the occurrence and development of hepatocellular carcinoma and the relationship between nMSI and mtMSI.

METHODS: nMSI was observed with PCR and mtMSI with PCR-SSCP in 52 cases of hepatocellular carcinoma.

RESULTS: mtMSI was detected in 11 out of the 52 cases of hepatocellular carcinoma (21.2%). Among the 11 cases of hepatocellular carcinoma with mtMSI, 7 occured in one locus and 4 in 2 loci. The frequency of mtMSI in the 52 cases of hepatocellular carcinoma showed no correlation to sex, age, infection of hepatitis B, liver cirrhosis as well as positive AFP of the patients (P > 0.05). In addition, nMSI was detected in 3 out of 52 cases of hepatocellular carcinoma (5.8%) and there was no correlation of the incidence of mtMSI to that of nMSI (P > 0.05).

CONCLUSION: mtMSI may be involved in the coccurrence and development of hepatocellular carcinoma and it is independent of nMSI.

N/A

N/A