TPL2 expression is correlated with distant metastasis and poor prognosis in colorectal cancer.

Tumor progression locus 2 (TPL2) is a mitogen-activated protein kinase (MAPK) kinase kinase (MAP3K). The present study aimed to elucidate the clinicopathological significance and prognostic role of TPL2 expression in colorectal cancer (CRC) through immunohistochemistry. In the present study, the correlations between TPL2 expression and clinicopathological parameters, including survival rate, were investigated using 262 archival paraffin-embedded CRC tissue samples. In addition, the correlation between TPL2 expression and tumor-infiltrating lymphocytes was evaluated using immunoscore. High TPL2 expression was found in 40.1% of the 262 CRCs analyzed. Patients with high TPL2 expression had frequent distant metastasis compared to patients with low TPL2 expression. However, there was no significant correlation between high TPL2 expression and other clinicopathological parameters. High TPL2 expression was significantly correlated with low immunoscore. In subgroup analysis based on distant metastasis, there was a significant correlation between high TPL2 expression and low immunoscore in only CRCs without distant metastasis. High TPL2 expression significantly correlated with poor overall survival. In both CRCs with and without distant metastasis, CRCs with high TPL2 expression showed worse prognosis compared to CRCs with low TPL2 expression (P = .034 and P = .010, respectively). Taken together, our results showed that high TPL2 expression was significantly correlated with distant metastasis and low immunoscore. In addition, TPL2 expression can be useful for predicting the prognosis of patients with CRC.