PURPOSE: Accumulating evidence suggests that cancer/testis antigens may serve as indicators of tumor malignant phenotype. The purpose of this study is to evaluate cancer/testis antigen genes in predicting metastasis of colorectal cancer to the liver.
METHODS: The expression levels of 25 cancer/testis antigen genes were determined by reverse-transcription polymerase chain reaction in 288 colorectal cancer tissue samples from the primary tumor or liver metastasis. Pearson χ2 and multiple logistic regression analyses were performed to assess the association between risk factors and probability of liver metastasis of colorectal cancer.
RESULTS: No significant difference was detected between the primary tumor and liver metastasis in expression pattern of cancer/testis antigen genes in colorectal cancer tissue samples. However, 3 cancer/testis antigen genes (PAGE4, SCP-1, and SPANX) and 3 clinicopathologic parameters (lymph node involvement, vessel cancer embolus, and tumor invasion depth) correlated significantly with liver metastasis of colorectal cancer (P < .05). A logistic regression model was constructed for prediction of liver metastasis based on a panel consisting of PAGE4, lymph node involvement, and presence or absence of vessel cancer embolus. The predicted risk of liver metastasis based on the panel was consistent with the actual risk observed. The probability of developing liver metastasis as estimated by the panel was 86.9% when all 3 factors were positive, representing an up to 20% improvement in the prediction level compared with the classic methods of lymph node involvement and vessel cancer embolus.
CONCLUSIONS: A new predictive panel including PAGE4 expression may help predict liver metastasis of colorectal cancer.