Expression And Significance Of S100A4 Gene In Colon Cancer

Objective:Colon cancer remains one of the most frequent malignant neoplasms of alimentary tract in China. When diagnosed, some patients have metastasis of lymph node and liver, and these patients have a poor outcome. Thus, the research of mechanism of metastasis of colon cancer has a significant clinical value. A lot of researches have confirmed that many genes and their products take part in metastasis of tumor. Among those, the expression of S100A4 gene can enhance metastasis of tumor and its high expression often prognosticates a poor outcome. Thus, S100A4 gene becomes a hot spot of research in recent years. However studies to investigate the relationship between S100A4 gene and colon cancer are fewer, and the result is contradictory. Our objective is to study the expression of S100A4 gene in colon cancer, and analyse its association with clinical and pathological character and outcome of patients.Methods:1. Studying the expression of S100A4 gene in HT29 and LoVo by RT-PCR;2. Selecting 61 patients of colon cancer from 2003-2005, and studying the expression of S100A4 RNA by in situ hybridization and S100A4 protein by immunohistochemistry;3. Using SPSS12.0 to carry out statistical analysis: comparing the positive rate of S100A4 in different samples byχ~2 test, analysing the relationship between the expression of S100A4 and clinical data and using Fisher's exact test to analyse the clinical data with a small number; comparing the survival rate of S100A4 positive patients and S100A4 negative patients by Kaplan-Meier, analysing the relationship between the expression of S100A4 gene and outcome of patients, and draw the survival curve.Results:1.the expression of S100A4 gene in colon cancer lines: S100A4 RNA was detected in both HT29 and LoVo, and the level of expression of S100A4 in these cells was close;2. the expression of S100A4 gene in colon cancer tissures:2.1 There was no expression of S100A4 gene or protein in non-cancerous tissue, and the positive rate of S100A4 gene and protein in colon cancer was 34.4% and 36.1% (p<0.001).2.2 The positive rate of S100A4 gene was seen in 0%(0/4) Dukes stage A cases, 12%(3/25) stage B cases, 46.7%(7/15) stage C cases and 64.7% (11/17) stage D cases(p=0.001). The positive rate of S100A4 protein was seen in 0%(0/4) Dukes stage A cases, 16%(4/25) stage B cases, 53.3%(8/15) stage C cases and 58.8% (10/17) stage D cases(p=0.006). 16 of 29(55.2%) cases with metastasis of lymph node have positive expression of S100A4 gene, while only 5 of 32(15.6%) cases without metastasis(p=0.001). 16 of 29(55.2%) cases with metastasis of lymph node have positive expression of S100A4 gene, while only 6 of 32(18.8%) cases without metastasis(p=0.001).3. the expression of S100A4 gene and prognosis:Kaplan-Meier analysis:The survival rate of S100A4 gene positive patients is significant lower than that of S100A4 gene negative patients(Log Rank:p=0.0268); similarly , the survival rate of S100A4 protein positive patients is significant lower than that of S100A4 protein negative patients(Log Rank:p=0.0009).Conclusions:The expression of S100A4 gene is elevated in colon cancer, and its expression is significantly associated with clinical stage of colon cancer and prognosis of patients with colon cancer. Thus, the expression of S100A4 gene is a valuable index to judge the biological behavior and prognosis of colon cancer.