Expression of MUC1 in esophageal squamous-cell carcinoma and its relationship with prognosis of patients from Linzhou city, a high incidence area of northern China

Table 3 All factors employed by Cox regression model

Factors	Variable
Sex	X1	0 = male, 1 = female
Age	X2	0 ≤ 45 years, 1 = 45~55 years, 2 ≥ 55 years
Invading depth	X3	0 = lamina propria or submucosa, 1 = muscularis propria, 2 = adventitia, 3 = adjacent structures
Regional lymph node metastasis	X4	0 = no, 1 = yes
Distant metastasis	X5	0 = no, 1 = yes
TNM stage	X6	0 = 0, 1 = I, 2 = II, 3 = III, 4 = IV
Differentiation	X7	0 = high, 2 = moderate, 3 = low
Expression of MUC1	X8	0 = low, 1 = high