| Objective:Colorectal cancer is one of the most common malignant tumors, and its mortality ratio is increasing recently, seriously threatening people's health. The reason is probably relative to no effective means of early diagnosis and assessment of prognosis. The imbalance of apoptosis and proliferation of colorectal mucosa can promote the formation of colorectal tumors. Smad7 and C-myc is promotion cell proliferation protein and Cycloxygenase-2 (Cox-2) is anti-apoptosis protein, which can promote the development of colorectal tumor. The effects of C-myc, Cox-2 on colorectal cancer have been reported, while the effect of Smad7 on the colorectal cancer has been seldom reported in China. Investigation on combined test for Smad7, C-myc, Cox-2 in colorectal cancer and adenomas has not been reported before. So we investigate the expression of Smad7, C-myc ,Cox-2 in colorectal cancer and adenomatous polyp and analyse the relationship with clinical data of colorectal cancer patients to find the correlation ship among them.Experimental Methods:50 cases in Sichuan Provincial People,s Hospital with surgical excision specimens of colorectal cancer with complete clinical data were included according to the standard of American Joint Committen on Cancer(AJCC) on TNM stage. 60 cases of colorectal adenomatous polyps in Sichuan Provincial People , s Hospital also included, 20 specimens of tubular adenoma,20 specimens of tubulovillous adenoma and 20 specimens of villous adenoma by hematoxylin and eosin stain. 20 cases for normal control were taken from the colorectal mucosa beyond 5cm to the end of colorectal cancer. EnVision-two-step immunohistochemistry is used to detect the expressions of Smad7, Cox-2,C-myc in colorectal carcinoma, colorectal adenomatous polyp and normal colorectal tissue.Statistical Methods:Statistical analysis was performed using SPSS for windows 16.0 software, test levelα= 0.05. X2 test was used to compare the expressions rate; The Spearman test was used for the correlation of expressions among Smad7, C-myc and Cox-2.Results:1. The positive expression rate of Smad7 in colorectal cancer and adenomatous polyp is 72%, 61.7% respectively, and in normal tissues is 25%, the difference among them is significant (P <0.001). The expression of Smad7 protein in colorectal cancer, adenomatous polyp is significantly higher than that in normal tissue (P <0.01), while the expression of Smad7 is no significant difference (p = 0.253) between adenomatous polyp and colorectal cancer. The positive expression rate of Smad7 in low and moderate differentiated group is higher than in high differentiated group(88.5%, 54.2%, P <0.05). The positive expression rate is 40% and 85.7% respectively in no infiltration serous layer and infiltration serous layer (P <0.01). The expression of Smad7 in colorectal cancer is no closed to patients' age, sex and the tumor size, location and TNM stage, lymph node metastasis (P> 0.05) .2. The positive expression rate of c-myc in adenomatous polyp and colorectal cancer is 30%, 50%, in normal colorectal tissues do not express (P<0.001). The expression of C-myc in colorectal cancer, colorectal adenomatous polyp are higher than normal tissue (P <0.01), significantly different between adenomatous polyp and colorectal cancer (P <0.05). Further analysis showed that the C-myc expression in colorectal cancer is related with tumor differentiation, lymph node metastasis, TNM stage. The positive expression rate of c-myc is in low and moderate differentiated group significantly higher than in high differentiated group(65.4%, 33.3%, P <0.05).The positive expression rate of C-myc in TNM stage III+IV group is higher than in I+II group(71.4%34.5%, P <0.05), as well as lymph node metastasis group and no metastasis group (68.4%, 38.7%, P <0.05). The expression of C-myc in colorectal cancer is no correlation (P> 0.05) to patients' age, sex and the tumor size, location and the depth of the infiltration.3. The positive expression rate of Cox-2 in adenomatous polyp and colorectal cancer is 46.7%, 70%, in normal colorectal tissues is 15%(P <0.001). The expression of Cox-2 in colorectal cancer,colorectal adenomatous polyp are higher than normal tissue (P <0.01, P <0.05), significantly different between adenomatous polyp and colorectal cancer (P <0.05). Further analysis showed that the Cox-2 expression in colorectal cancer is related with tumor differentiation, lymph node metastasis, TNM stage. The positive expression rate of Cox-2 in low and moderate differentiated group is higher than in high differentiated group(88.5%, 50%, P <0.01).The positive expression rate of Cox-2 in TNM stage III+IV group is higher than in I+II group(85.7%,58.6%, P <0.05), as well as lymph node metastasis group and no metastasis group (89.5%, 58.1%, P <0.05). The expression of Cox-2 in colorectal cancer is no correlation (P> 0.05) to patients' age, sex and the tumor size, location and the depth of the infiltration. 4. The expression rate of Smad7,C-myc,Cox-2 in tubular adenoma, tubulovillous adenoma and villous adenoma are 55%, 60%, 70%; 20%, 30%, 40%; 25%, 55%, 60% respectively(P> 0.05).5. The expression rate of Smad7, C-myc are significantly correlated with the positive expression rate of Cox-2.The correlation coefficients are 0.28, 0.283, (P<0.05) respectively. The Smad7 expression rate was significantly correlated with the positive expression rate of C-myc and the correlation coefficient is 0.476 (P <0.01).Conclusion:1. The expressions of Smad7,C-myc, Cox-2 increase in colorectal tumor, suggesting that Smad7,C-myc by promoting cell proliferation and Cox-2 by inhibiting the apoptosis promote colorectal tumor genesis .2. The expression of Smad7 is related to the degree of differentiation, depth of invasion of colorectal cancer. The lower of differentiation and the deeper of invasion, the higher expression of Smad7. The expression of C-myc is related to differentiation of colorectal cancer, lymph node metastasis, TNM stage, etc. The lower of differentiation and the later of TNM stage, the higher expression of C-myc, as well as lymph node metastasis group suggested that Smad7, C-myc may be associated with the prognosis of patients with colorectal cancer.3. The expression of Cox-2 is related to differentiation of colorectal cancer, lymph node metastasis, TNM stage etc. The lower of differentiation and the later of TNM stage, the higher expression of Cox-2, as well as lymph node metastasis group suggested that Cox-2 may be helpful to assess the prognosis of patients with colorectal cancer. 4. The expression rate of Smad7, C-myc and Cox-2 in colorectal cancer is correlated with each other. Suggestion Smad7, C-myc influence on cell proliferation and Cox-2 effect apoptosis together play an important role in the colorectal tumor genesis and progression. Combined test Smad7, C-myc and Cox-2 in colorectal cancer may be helphul to assess the prognosis of patients and to choose reasonable therapy for colorectal cancer patients.
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