Relationship between copy number of mitochondrial DNA and prognosis of patients in colorectal cancer / 中华消化杂志

ABSTRACT

Objective To explore the relationship between abnormal copy number of mitochondrial DNA (mtDNA) and prognosis of the patients in colorectal cancer (CRC).Methods A total of 60 cases of CRC and corresponding adjacent noncancerous tissue specimens were selected.Genomic DNA was extracted.The mitochondrial ND1 gene was detected by quantitative real-time polymerase chain reaction and β-actin was set as internal control.And then the copy number of mtDNA was caculated and analyzed by t-test.The prognosis of patients was determined by Kaplan-Meier survival analysis.Results The mean mtDNA copy number of CRC tissue was 108.60±20.11,while that of the corresponding adjacent noncancerous tissues was 153.68±25.72,the former was significantly lower than that of the latter (t=10.69,P＜0.01).The rate of low mtDNA copy number in case with positive lymph nodes metastasis was higher than that in cases with negative lymph nodes metastasis (x2 =4.022,P＜0.05),however there were no obvious correlation with gender,age,pathological type,TNM stage.The survival rate of high mtDNA copy number group was higher than that of low mtDNA copy number group,however there was no statistical significance (P＞ 0.05).Conclusions mtDNA copy number of CRC was significantly lower than that of the adjacent noncancerous tissues.However the change of copy number was not correlated to the prognosis.