Expression And Significance Of FMN2 In Colorectal Cancer

FMN2, a novel formin homolo gy protein of the cappuccino subfamily, was first discovered by Leader and Leder in 2000. Their research shows that, in the murine model, Fmn2 is expressed almost exclusively in the developing and mature central nervous system including the olfactory bulb, cortex, thalamus, hypothalamus, hippocampus and cerebellum. The subsequent result indicate that FMN2 m RNA was expressed in fetal brain, adult whole brain, hypothalamus, retina, pancreatic islet and germinal-center B cells. Among various human tumors, FMN2 is related with parathyloid tumor, glioblastoma, retinoblastoma, chondrosarcoma and leukemia. In mouse oocytes, FMN2 involve in actin filament elongation in oocyte meiosis and impact of the neoplasms invasion and metastasis. Among the suddies of human tumors on FMN2, its value as a tumor suppressor gene or a oncogene remains elusive. So far, the expression pattern and the role of FMN2 in CRC tissue are poorly understood. In this study, FMN2 expression was assessed to anslyze its prognosis in CRC patients using tissue microarrays by immunohistochemistry.In order to clarify issues raised above, the present study:1. Investigated the FMN2 expression pattern by immunohistochemistry in 20 cases of randomized selected samples and matched adjacent tissues preliminarily. 2. Manufactured tissue microarray by 335 cases of colorectal cancer samples recruited in Xijing Hospital of Digestive Diseases. Collected complete clinicopathological data and prognosis information. 3. Disclosed the FMN2 expression pattern using tissue microarrays by immunohistochemistry in selected 335 samples and matched adjacent tissues. 4. Analyzed FMN2 association with clinicopathological data with colorectal cancer by chi-square test or Fisher’s exact test. 5. Analyzed FMN2 association with prognosis information of patients with colorectal cancer by Kaplan-Meier.The results of the researchs above showed that: 1. Among the 20 cases of selected colorectal carcinoma samples and matched adjacent tissues in the pre-experiment, immunohistochemistry showed the positive expression rate was 55.0%(11/20), and negative expression rate was 45.0%(9/20) in the CRC tissue. the positive expression rate was 85.0%(17/20), and negative expression rate was 15.0%(3/20) in the matched adjacent tissues. Result showed that decreased expression of FMN2 CRC, compared with matched adjacent tissues, which showed a decreased expression trend of FMN2 in CRC(c2=4.29,R<0.05).2. Among the 335 cases in tissue microarray of CRC tissues and matched adjacent tissues in the immunohistochemistry, result showed the positive expression rate was 53.7%, and negative expression rate was 46.3%in the CRC tissue. the positive expression rate was 80.9%, and negative expression rate was 19.1% in the matched adjacent tissues. The data of tests suggested that the CRC tissues and matched adjacent tissues positive expression was significant(c2=46.9,R<0.01),which suggested that FMN2 was a probable candidate for a tumor suppressor gene in CRC.3. The results of immunohistochemistry assay on tissue microarray showed that tumor differentiation, TNM stage, lymph node metastasis were significantly correlated with the expression of FMN2(R<0.05). Gender, age and tumor location were not significant associated with FMN2 expression(R >0.05). Above results suggested that CRC patients with lower FMN2 expression had a lower grade of differentiation, later TNM stage and more lymph node metastasis then higher FMN2 expression.4. Analyzed the 335 cases in tissue microarray of CRC tissues by Kaplan-Meier method, the tesult showed that 149 cases were FMN2 positive expression, 3 year overall survival rate was 68.45%, median survival time >36 months. 173 cases were FMN2 negative expression, 3 year overall survival rate was 48.62%, median survival time was 26 months. Suggested that patients with lower FMN2 expression showed shorter overall survival and disease-free survival time than higher FMN2 expression(log-rank test: R<0.05).These results above proved that: 1. The expression of FMN2 was decreased in CRC. FMN2 was a probable candidate for a tumor suppressor gene in CRC.2. Decreased expression trend of FMN2 were significantly correlated with tumor differentiation, TNM stage and lymph node metastasis. FMN2 may be an important marker reflecting CRC development, invasion and metastasis of.3. CRC patients with lower FMN2 expression showed shorter overall survival and disease-free survival time than higher FMN2 expression. FMN2 was a good prognostic marker for CRC patients.