Table 1.

Patient details and clinicopathological characteristics

	ESCC (n = 125)		Normal (n = 125)
	N	%	N	%
Sex
Male	76	60.8	76	60.8
Female	49	39.2	49	39.2
Age (y)
Range	41‐80		40‐79
Median (P25 ~ P75)	63 (59 ~ 68)		63 (59 ~ 68)
Site of tumor
Upper esophagus	22	17.6
Middle esophagus	65	52
Lower esophagus	31	24.8
Unknown	7	5.6
Histological grade
High (grade 1)	15	12
Middle (grade 2)	46	36.8
Low (grade 3)	50	40
Unknown	14	11.2
TNM stage
0	7	5.6
I	47	37.6
II	38	30.4
III	24	19.2
IV	5	4
Unknown	4	3.2
Depth of tumor invasion
Tis	7	5.6
T1	43	34.4
T2	20	16
T3	48	38.4
T4	0	0
Unknown	7	5.6
Lymph node metastasis
Negative	86	68.8
Positive	32	25.6
Unknown	7	5.6
Distant metastasis
No	116	92.8
Yes	5	4
Unknown	4	3.2

Abbreviations: ESCC, esophageal squamous cell carcinoma; P₂₅, upper quartile, P₇₅, lower quartile.