LEVEL OF LARGE DELETIONS OF MITOCHONDRIAL DNA IN COLORECTAL CANCER PATIENTS

Pham Thi Bich1, Ta Van To2, Trinh Hong Thai3
1 Khoa Sinh học, Trường Đại học Khoa học Tự nhiên
2 Bộ môn Giải phẫu bệnh - Tế bào, Bệnh viện K
3 Phòng thí nghiệm Trọng điểm Công nghệ Enzyme và Protein, Trường Đại học Khoa học Tự nhiên

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Abstract

Objectives: To determine the level of large-scale deletions of mitochondrial DNA in tumor tissues, tumor-adjacent normal tissues and blood samples from patients with colorectal cancer; thereby, evaluating the relationship between the levels of these deletion with clinico-pathological characteristics, comparing the level of these deletions in blood samples obtained from cancer patients and normal healthy people (serves as controls). Methods: The level of large-scale deletions was determined by quantitative PCR (real-time PCR). The relationship between the level of deletion and the pathological characteristics of colorectal cancer was also tested by using suitable statistic methods. A total of 94 patients with colorectal cancer were analyzed. In which, 54 paired tumor and tumor-adjacent normal tissues form 54 patients were provided by Vietnam National Cancer Hospital; 40 paired tumor and adjacent normal tissues associated with blood samples from 40 patients were provided by Military Hospital 103. Blood samples of 67 normal healthy people were used as controls. Results: The obtained results showed that the levels of large-scale deletions of mitochondrial DNA in tumor tissue, tumor-adjacent normal tissues, blood patient’s samples and blood control samples were 56.89%, 58.09%, 59.37% and 53.61%, respectively. The level of large deletions in the patient's blood sample was higher than in the control blood sample (p < 0.05). The level of large-scale deletions of mitochondrial DNA was independent of age, sex and pathological features. Conclusions: The level of large-scale deletions in the range of 50-60% was mostly found in the subjected patients. The mtDNA deletion level in the patients’ blood sample was significantly higher than that in the control sample (p < 0.05). The deletion level was not associated with clinico-pathological characteristics of the studied patients. There was a weak correlation of deletion level between tissue samples and blood samples of patients with colorectal cancer (p > 0.05).

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