Background
Methods
Patients
Characteristics | No. of patients (%) |
---|---|
Gender | |
Male | 84 (81.5) |
Female | 19 (18.5) |
Age, years | |
Mean | 58.8 |
SD | 12.9 |
Tumor localization | |
gastric cardia | 20 (19.4) |
gastric body | 32 (31.1) |
gastric antrum | 51 (49.5) |
Tumor size (cm3) | |
≤3 | 32 (31.1) |
3-5 | 36 (35.0) |
>5 | 35 (33.9) |
Differentiation | |
well/moderate | 48 (46.6) |
poor/undifferentiation | 55 (53.4) |
Tumor invasion | |
T1 | 23 (22.3) |
T2 | 14 (13.6) |
T3 | 52 (50.5) |
T4 | 14 (13.6) |
TNM stage | |
I | 9 (8.7) |
II | 41 (39.8) |
III | 47 (45.6) |
IV | 6 (5.8) |
Lymph node metastasis (LNM) | |
Yes | 48 (46.6) |
No | 55 (53.4) |
No. of LNM | |
N0 | 55 (53.4) |
N1 (1–6) | 34 (33.0) |
N2 (7–15) | 10 (9.7) |
N3 (≥16) | 4 (3.9) |
Survival status | |
Dead | 45 (43.7) |
Alive | 58 (56.3) |
DNA preparation
mtDNA copy number analysis
Genes | Forward primer sequence (5′→3′) | Probe sequence (5′→3′) | Reverse primer sequence (5′→3′) | Amplification efficiency (%) |
---|---|---|---|---|
MT-ND1
| CCCCTAAAACCCGCCACATC | 6FAM-ACCCTCTACATCACCGCCCCGACC-TAMRA | GTAGAAGAGCGATGGTGAGAGC | 93.6 |
β-actin
| TCACCCACACTGTGCCCATCTACGA | 6FAM-ATGCCCTCCCCCATGCCATCC-TAMRA | TCGGTGAGGATCTTCATGAGGTA | 95.7 |
Statistical analysis
Results
Relative mtDNA copy number in gastric cancer
Association of variable mtDNA content with clinicopathological characteristics of gastric cancer patients
Characteristics | Copy number <3.61 | Copy number >5.35 | ||
---|---|---|---|---|
OR*(95% CI) |
P
| OR*(95% CI) |
P
| |
Male vs. Female | 1.55 (0.42-5.70) | 0.51 | 1.75 (0.37-8.30) | 0.48 |
Age1 | 1.00 (0.65-1.52) | 0.98 | 1.10 (0.67-1.79) | 0.71 |
Tumor localization2 | 1.11 (0.51-2.42) | 0.80 | 1.22 (0.50-2.99) | 0.66 |
Tumor size3 | 1.31 (0.66-2.60) | 0.45 | 1.37 (0.63-3.01) | 0.43 |
Differentiation4 | 1.78 (0.58-5.49) | 0.32 | 1.11 (0.31-4.04) | 0.87 |
Tumor invasion5 | 0.82 (0.46-1.47) | 0.50 | 0.69 (0.36-1.34) | 0.27 |
TNM stage6 | 0.84 (0.40-1.78) | 0.65 | 0.86 (0.36-2.03) | 0.73 |
Lymph node metastasis | 4.93 (1.28-19.04) | 0.02 | 4.00 (0.91-17.58) | 0.07 |
Survival status7 | 1.20 (0.39-3.73) | 0.75 | 1.81 (0.50-6.50) | 0.37 |
Characteristics | Copy number <3.61 | Copy number >5.35 | ||
---|---|---|---|---|
OR*(95% CI) |
P
| OR*(95% CI) |
P
| |
Male vs. Female | 1.16 (0.11-12.13) | 0.90 | 0.80 (0.06-11.30) | 0.87 |
Age1 | 0.48 (0.05-4.65) | 0.53 | 0.20 (0.02-2.39) | 0.20 |
Tumor localization2 | 3.65 (0.91-14.64) | 0.07 | 2.78 (0.59-13.0) | 0.19 |
Tumor size3 | 0.80 (0.24-2.65) | 0.71 | 0.56 (0.13-2.32) | 0.42 |
Tumor invasion4 | 0.49 (0.16-1.49) | 0.21 | 0.28 (0.08-0.99) | 0.049 |
Lymph node metastasis | 1.09 (0.17-6.85) | 0.93 | 0.86 (0.10-7.51) | 0.90 |
Survival status5 | 0.42 (0.07-2.43) | 0.33 | 0.25 (0.03-2.32) | 0.22 |
Characteristics | Copy number <3.61 | Copy number >5.35 | ||
---|---|---|---|---|
OR*(95% CI) |
P
| OR*(95% CI) |
P
| |
Male vs. Female | 1.57 (0.31-7.99) | 0.59 | 2.79 (0.37-20.82) | 0.32 |
Age1 | 0.67 (0.15-2.89) | 0.59 | 1.33 (0.25-7.01) | 0.73 |
Tumor localization2 | 0.44 (0.13-1.45) | 0.18 | 0.70 (0.19-2.616) | 0.60 |
Tumor size3 | 1.86 (0.78-4.42) | 0.16 | 2.10 (0.79-5.57) | 0.14 |
Tumor invasion4 | 1.13 (0.53-2.41) | 0.74 | 1.16 (0.50-2.69) | 0.73 |
Lymph node metastasis | 27.00 (2.89-252.62) | 0.004 | 13.50 (1.34-135.98) | 0.03 |
Survival status5 | 3.11 (0.66-14.60) | 0.15 | 6.42 (1.09-37.74) | 0.04 |
Characteristics | Copy number <3.61 | Copy number >5.35 | ||
---|---|---|---|---|
OR*(95% CI) |
P
| OR*(95% CI) |
P
| |
Age1 | 0.80 (0.49-1.31) | 0.38 | 0.96 (0.56-1.65) | 0.89 |
Tumor size2 | 0.91 (0.43-1.92) | 0.80 | 1.04 (0.46-2.36) | 0.92 |
Differentiation3 | 3.00 (0.86-10.47) | 0.08 | 1.56 (0.39-6.19) | 0.53 |
Lymph node metastasis | 7.63 (1.63-35.69) | 0.01 | 4.41 (0.84-23.12) | 0.08 |
Effect of variable mtDNA content on poor survival of gastric cancer patients
Univariate analysis | Multivariate analysis | |||
---|---|---|---|---|
Variable | Hazard ratio (95% CI) |
P
| Hazard ratio (95% CI) |
P
|
Copy number | ||||
3.61~5.35 | 1.00 (reference) | 1.00 (reference) | ||
<3.61 | 1.51 (0.44-2.57) | 0.90 | 0.52 (0.20-1.38) | 0.19 |
>5.35 | 1.53 (0.58-4.02) | 0.39 | 1.07 (0.37-3.07) | 0.90 |
The number of lymph node metastasis | ||||
0 | 1.00 (reference) | 1.00 (reference) | ||
1~6 | 6.86 (3.18-14.91) | <0.001 | 7.28 (2.87-18.49) | <0.001 |
7~15 | 6.41 (2.70-15.25) | <0.001 | 4.68 (1.65-13.28) | 0.004 |
≥16 | 16.75 (5.05-55.56) | <0.001 | 13.21 (3.33-52.45) | <0.001 |
Tumor invasion | ||||
T1 | 1.00 (reference) | 1.00 (reference) | ||
T2 | 0.85 (0.16-4.67) | 0.86 | 0.63 (0.11-3.54) | 0.60 |
T3 | 4.36 (1.53-12.42) | 0.006 | 1.51 (0.46-4.92) | 0.49 |
T4 | 2.66 (1.30-5.48) | 0.001 | 3.33 (0.92-12.14) | 0.07 |
Differentiation | ||||
Well/moderate | 1.00 (reference) | 1.00 (reference) | ||
Poor/undifferentiation | 2.22 (1.19-4.19) | 0.01 | 1.82 (0.86-3.82) | 0.12 |