Association of p53/p21 expression with cigarette smoking and prognosis in esophageal squamous cell carcinoma patients

Table 1 Distribution of the demographic variables for esophageal squamous cell carcinoma cases and healthy subjects n (%)

	Case	Control	P value1
Age (yr)
< 60	36 (45)	27 (33.8)	NS
≥ 60	44 (55)	53 (66.2)
Gender
Male	45 (56.2)	48 (60)	NS
Female	35 (43.8)	32 (40)
Smoking
Never	52 (65)	28 (35)	0.03
Ever	64 (80)	16 (20)
Opium use
Ever	21 (26.2)	18 (22.5)	NS
Never	59 (73.8)	62 (77.5)
p53 expression
Positive	45 (56.2)	0 (0)	< 0.001
Negative	35 (43.8)	80 (100)
p21 expression
Positive	59 (73.8)	37 (46.2)	< 0.001
Negative	21 (26.2)	43 (53.8)

¹Not statistically significant by χ² test. NS: Not significant.