AB060. A4164G alteration of mitochondrial MT-ND1 gene in a Vietnamese patient group with colorectal cancer
Pham Thi Bich1, Hoang Thi Chang1, Do Minh Ha1, Ta Van To2, Trinh Hong Thai1
Background and objective: Colorectal cancer (CRC) is one of the most common cancers which is increasing all over the world and in Vietnam. Many causes of disease have been identified, including variations in nuclear genes and mitochondrial genes. The MT-ND1 gene is located in the heavy strand of mitochondrial DNA and encodes NADH dehydrogenase 1 protein. Some mutations were detected in mitochondrial DNA of CRC patients such as T3394C, T4216C and C3497T. These mutations occur in high conservative region, thus can effect on structure and function of the NADH dehydrogenase 1. In this study, we investigated the incidence of A4164G and T4216C alterations of mitochondrial MT-ND1 gene in Vietnamese CRC patients and whether these alterations might be associated with some pathological characteristics of CRC.
Methods: A total of 107 Vietnamese CRC patients and 100 controls were determined for A4164G and T4216C alterations by using PCR-RFLP and sequencing methods. Relationship between the genotype and pathological characteristics of CRC patients was calculated by using χ2 test. Odds ratio and 95% confidence interval were calculated as an estimate of the relative risk.
Results: The results showed that there were 14.95% CRC tissue samples, 10.53% cancer blood samples and 9% blood control samples with the A4164G alteration in the MT-ND1 gene. T4216C mutation was not found in those samples. There was no difference of A4164G distribution in subgroups of age, gender, size of tumor (P>0.05), but difference in site of tumor and TNM (lymph-node-metastasis) stage (P<0.05). The A4164G alteration was only found in 22.22% blood samples of CRC patients which had A4164G alteration in the tissue samples. So A4164G alteration can be a somatic mutation in these CRC patients.
Conclusions: The difference of A4164G alteration between tumor tissue, adjacent tissue and blood of the same patient in some CRC cases can be considered as an evidence of somatic mutation in these CRC patients in Vietnam.
Keywords: A4164G alteration; colorectal cancer (CRC); MT-ND1; PCR-RFLP; sequencing
