TABLE 3.

Comparison of cfDNA Basic Characteristics and TMB Between Two Groups.

Indicator	Benign group (n = 128)	Malignant group (n = 84)	Statistics	P value
cfDNA concentration (ng/mL, x̄±s)	8.6 ± 3.2	14.3 ± 5.8	t = 8.426	<0.001
Short fragment proportion (%) (a) [M(Q1,Q3)]	12.4 (9.2,15.8)	18.7 (14.3,24.5)	Z = −6.745	<0.001
Mononucleosome fragment proportion (%, x̄±s)	62.8 ± 8.4	56.2 ± 9.7	t = −5.236	<0.001
Dinucleosome fragment proportion (%, x̄±s)	21.5 ± 5.2	20.8 ± 6.1	t = −0.876	0.382
Polynucleosome fragment proportion (%) [M(Q1,Q3)]	3.2 (2.1,4.8)	3.6 (2.3,5.2)	Z = −1.234	0.217
SFR(b) [M(Q1,Q3)]	0.78 (0.62,0.95)	1.24 (0.96,1.58)	Z = −7.892	<0.001
TMB (mut/Mb) [M(Q1,Q3)]	0.39 (0.27,0.68)	1.31 (0.99,1.63)	Z = −10.406	<0.001

(a) Short fragment proportion refers to the percentage of cfDNA, with fragment length <120 bp; (b) SFR (short fragment ratio) is defined as the ratio of fragment count <150 bp to fragment count [150 bp, 250 bp).