The Correlation Study On High ASS1 Expression And The Malignant Progression Of Colorectal Cancer

Background:This study was to investigate the clinical significance of ASS1 in the malignant progression of human colorectal cancer (CRC).Methods:The protein levels of ASS1 expression in human colon cancer cell lines, colorectal cancer and the matched paracancerous tissues were examined using Western blot. Immunohistochemistry was performed to analyze ASS1 expression in 150 clinicopathologically characterized colorectal cancer cases. The correlation between ASS1 expression and the malignant progression of colorectal cancer was analyzed with the spss 16.0 statistical software.Results:All colon cell lines HCT116 and SW1116 expressed ASS1, but significantly higher level of ASS1 expression was found in SW1116 cell line. ASS1 was notably upregulated in colorectal cancer tissues compared with the matched paracancerous tissues. Of the 150 cases of colorectal cancer, high level of ASS1 expression was found in 72 (48%) of them, whereas 78 (52%) of them displayed low expression (undetectable or marginally detectable). High expression of ASS1 in CRC patients was associated with regional lymph nodes, lymphatic invasion, perineural invasion, extranodal tumor deposit, distant metastasis, and TNM stage (P=0.003, P=0.001, P=0.014, P=0.030, P=0.003, P=0.001). The univariate analyses revealed that high ASS1 expression was associated with poorer overall survival time after operation (X2=17.449, P=0.000). Further multivariate analyses showed that ASS1 was an independent prognostic factor for colorectal cancer (RR=5.1,95%C11.539-16.900, P=0.008). Besides, high ASS1 expression could upregulate or down regulate some proteins that is correlated with colorectal cancer progression, such as high ASS1 expression could upregulate N-cadherin、 MMP-1、HIF-1α protein, and down regulate E-cadherin protein.Conclusions:This study indicated that ASS1 is associated with the malignant progression of colorectal cancer and is an independent prognostic factor for this disease. Therefore, ASS1 may be a potential therapeutic target as expected.