Table 1. The correlation between PIK3CA hypomethylation and demographic features of esophageal cancer patients.

	n	Average methylation rate (%)	P-value
Total number	32	6.00±2.80	–
Age≤45 years >45 years	8 24	5.77±2.51 6.74±3.63	t=−0.845, P=0.405
Male Female	23 9	5.79±2.63 6.56±3.30	t=−0.689, P=0.496
Tumor size≤3 cm 3–5 cm ≥5 cm	5 23 4	6.94±4.53 5.85±2.23 5.77±3.93	F=0.318, P=0.730
Positive lymph nodes Negative lymph nodes	14 18	5.49±2.76 6.41±2.84	t=−0.917, P=0.366
TNM stage I TNM stage II TNM stage IIIa+IIIb, IV	6 16 10	8.52±2.55 6.42±2.36 3.84±2.08*	PI–III=0.001 PII–III=0.01

Comparisons of single samples were performed with the Student's t-test and ANOVA test.

^*, Stage III and IV specimens were analyzed in one category.