Polarization of Cytokine Profile from Th1 into Th2 Along Colorectal Adenoma- Carcinoma Sequence: Implications for the Biotherapeutic Target?

The development of colorectal carcinoma (CRC) has been hypothesized to be raised mostly from the precancerous lesion of colorectal adenoma (CRA) through a multistep process and defined as the adenoma-carcinoma sequence. In response to the tumorigenesis, host cellular immunity acts as the most important defense factor with cytokines as the main regulator molecules. Therefore, changes of cytokines of the T helper 1 (Th1)/T helper 2 (Th2) type immune responses along this sequence may therefore reflect a functional switch of host anti-tumor immunity. This minireview focused on the recent knowledge of the Th1/Th2 balance in the adenoma-carcinoma sequence and its potential clinical and therapeutical significance.