Table 1.

Correlation of mtDNA content in breast cancer with clinicopathological features.

		mtDNA content in tumor tissue		T/N ratio of mtDNA content
	n	Mean ± SD	P value*	Mean ± SD	P value*
Age (years)
<40	56	592 ± 530		0.861 ± 0.561
40–49	103	588 ± 473	0.603	0.967 ± 0.7	0.817
50–59	77	574 ± 515		0.956 ± 0.92
≥60	57	577 ± 402		0.956 ± 0.849
Tumor size (cm3)			(versus C)		(versus C)
A: ≤4.9	79	735 ± 412	4.06e − 07	1.088 ± 0.636	1.84e − 05
B: 5~14.9	66	574 ± 354	0.004	1.000 ± 0.556	0.002
C: 15–49.9	75	372 ± 248		0.696 ± 0.459
D: ≥50	53	535 ± 385	0.306	0.818 ± 0.553	0.258
Grade
0~I	18	669 ± 412		0.995 ± 0.681
II	125	506 ± 318	0.019 (versus 0~I)	0.791 ± 0.531	0.827 (versus 0~I)
III	98	648 ± 432	0.383 (versus 0~I) 0.006 (versus II)	1.128 ± 0.988	0.441 (versus 0~I) 0.033 (versus II)
ER
Negative	107	502 ± 405	0.103	0.810 ± 0.612	0.047
Positive	157	573 ± 374		1.057 ± 1.059
PR
Negative	100	494 ± 352	0.061	0.839 ± 0.633	0.059
Positive	154	597 ± 384		1.034 ± 0.772
ER/PR
A:ER,PR both − or either +	134	473 ± 316	0.005	0.837 ± 0.536	0.355
B: ER+/PR+	129	618 ± 381		0.930 ± 0.617
Her2/neu receptor
Negative	56	444 ± 333	0.101	0.727 ± 0.518	0.023
Positive	168	531 ± 346		1.127 ± 1.184

*P values are from Mann-Whitney or Kruskal-Wallis test. The P values <0.05 are in bold, indicating significance; the P values >0.05, but <0.15 are in italic, indicating weak significance.