Table 1. Correlation analysis of Smad4 level, p-ERK level, and the TNM grade in colorectal cancer samples.

Smad4 IHC grade		p-ERK IHC grade		TNM stage
low expression	high expression	low expression	high expression	I and II	III	IV
41	12	18	35	15a	16	22

Smad4 and p-ERK level correlation analysis: Spearman r = -0.374, P = 0.006. Smad4 IHC grade and TNM stage correlation analysis: Spearman r = -0.294, P = 0.033. p-ERK IHC grade and TNM stage correlation analysis: Spearman r = 0.193, P = 0.166. ^aTwo cases were stratified into TNM stage I, which combined with 15 cases of TNM stage II for the Spearman correlation analysis.