Abstract: Objective To explore the possible roles of WNK2,MEK-1 and ERK1/2 in the carcinogenesis of sporadic colorectal tubular adenoma. Methods The protein expression of WNK2,MEK-1 and ERK1/2 were studied in 112 cases of sporadic colorectal tubular adenoma with different dysplasia(SCTA-D)and sporadic colorectal tubular adenoma with cancerous changes(SCTA -Ca)by immunohistochemical staining method. ResultsImmunohistochemical staining results showed the positive expression rate of WNK2 continuously decreased that was 100%,70% and 42.86% respectively in normal colorectal mucosa(NCM)，SCTA-D and SCTA-Ca,while the positive expression rates of MEK-1 and ERK1/2 were obviously increased(P＜0.05).The positive expression rate of MEK-1 and ERK1/2 in SCTA-D or SCTA-Ca was significantly higher than that in NCM(P＜0.05).The positive expression rate of WNK2 was gradually decreased,while MEK and ERK gradually increased from mild to severe dysplasia degree in the cases of SCTA-D(P＜0.05).Negative correlation could be found between WNK2 and MEK-1 or ERK1/2(r=-0.372，r=-0.371，P＜0.05).Positive correlation could be found between MEK-1 and ERK1/2(r=0.475,P＜0.05). Conclusion WNK2 may involve in the carcinogenesis of sporadic colorectal tubular adenoma through down-regulation of MEK-1 and ERK1/2.