| Backgroud: Tumor is one of the most common human diseases in the world, which is a multi-gene, multi-factor disease. Recently, the morbidity and mortality of malignant tumors is high, and showing a rising trend. High rate of invasion and metastasis is the key factor to influence the prognosis of patients. It is an important biological feature of malignant tumors with many genes abnormal expresed which involved in the invasion and metastasis. So analyzing the gene and protein expression profiles of malignant tumors, and exploring the change of gene and protein are valuable in finding the metastasis-related genes and proteins. It would be helpful to indicate the prognosis of patients. Egfl7 is a newly discovered gene as well as an important stimulating factor which could significantly enhance the ability of cell migration. Egfl7 overexpressed in several cancer cell lines, so we presume Egfl7 may play an important role in the invasion and metastasis of malignant tumors. However, the expression profiles of Egfl7 in human tumors and adult human normal tissues remain unknown, and its role in recurrence and metastasis of tumor is also unclear.Aim: To investigate the mRNA and protein expression profiles of Egfl7 gene in human epithelial tumors tissues, cancer cell lines and adult human normal tissues. To analyze its cellular localization in human cancer cells. To evaluate the correlation between Egfl7 gene expression and clinicopathological features as well as prognosis of HCC and breast cancer. To explore its role in recurrence and metastasis. To provide a novel tumor marker for judging the prognosis of HCC as well as breast cancer. To lay the foundation for researching its role in development of tumor.Method: Reverse transcription-polymerase chain reaction (RT-PCR) and Western blot were used to examine the mRNA and protein expression level of Egfl7 gene in 3 cases of 19 kinds of adult human normal tissues, 10 kinds of cancer cell lines, 36 HCC, 30 breast cancer, 30 lung cancer, 30 colorectal cancer, 30 gastric cancer, 3 malignant gliomas, 3 ovarian cancer, 3 kidney cancer, 4 prostate cancer and 5 esophageal cancer. The sub-cellular location of protein Egfl7 in cancer cell lines was examined by Cell Immunofluorescence. The Egfl7 protein expressions and distribution were examined by Immunohistochemistry in 132 HCC, 102 breast cancer, 30 lung cancer, 30 colorectal cancer, 30 gastric cancer, 8 malignant gliomas, 6 ovarian cancer, 16 kidney cancer, 8 prostate cancer and 10 esophageal cancer. We compared the difference of Egfl7 mRNA and protein expression levels between tumor tissues and nontumorous tissues, and investigated the correlation between Egfl7 expression and clinicopathological features of HCC and breast cancer, and the correlation between Egfl7 protein expression and prognosis of HCC as well as breast cancer patients.Result: The results of RT-PCR and Western blot showed that Egfl7 was a little differently expressed in adult human normal tissues, and was higher expressed in lung and retinal tissues. The mRNA and protein expression of Egfl7 in 10 common human epithelial tumors tissues were significantly higher than those in nontumorous tissues (P<0.05). Egfl7 was expressed differently in 10 cancer cell lines and located in cytoplasm of cancer cells. Immunohistochemistry showed that Egfl7 protein in epithelial tumor slides was mainly expressed in cytoplasm, the expression of Egfl7 in tumors tissues were significantly higher than those in nontumorous tissues (P<0.05).The high Egfl7 protein expression in HCC was significantly correlated with vein invasion (P = 0.020), multiple nodes (P = 0.036) and without capsular formation (P = 0.026), but existed no correlation with gender, age, cirrhosis, diameter of tumor or Edmondson- Steiner grade (P>0.05). Up-regulation of Egfl7 protein expression in breast cancer was strongly correlated with TNM stage(P = 0.011), lymphatic metastasis(P = 0.006), ER (P = 0.033)and Her-2(P = 0.025), but there was no significant association between Egfl7 expression and the other clinicopathological parameters, such as age, size of the tumor, pathologic types, histological grade or PR (P> 0.05).Our results showed that Egfl7 protein expression was negatively correlated with the prognosis of HCC and breast cancer. In HCC the survival time and disease-free survival time of Egfl7 protein high expression group were significantly shorter than those of Egfl7 protein low expression group(median survival time 410 vs 640 days, P =0.001; median disease free survival time 315 vs 560 days, P =0.007). In breast cancer the survival time and disease-free survival time of Egfl7 protein high expression group were significantly shorter than those of Egfl7 protein low expression group(median survival time 1900 vs 2710 days, P =0.001; median disease free survival time 1450 vs 2110 days, P =0.018). By multivariable Cox regression analysis, high Egfl7 expression was found to be an independent prognostic factor for survival.Conclusion: We first established the expression profiles of Egfl7 gene in 19 kinds adult human normal tissues, 10 kinds human epithelial tumors cell lines and tissues, to lay the foundation for researching its role in development of tumor. We analyzed the association between Egfl7 expression and the prognosis of HCC and breast cancer for the first time, the increased expression of Egfl7 was involved in the poor prognosis of HCC and breast cancer, it indicated Egfl7 might be a novel prognostic marker for cancer. We first confirmed cancer cells could secrete Egfl7 protein and it located in cytoplasm of cancer cells, it indicated that Egfl7 might be a novel serum diagnostic biomarker to monitor the recurrence and metastasis of HCC and judge its prognosis. |
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