| Objective: Colorectal cancer is a common digestive malignant tumors which harms to human life and health, whether it is in the world or China, its incidence and mortality are at the forefront. Occurrence of colorectal cancer is a very complex process including multi-factors and multi-ways which involved multiple oncogenes and tumor suppressor genes in the regulation. Spread and metastasis is one of the biological characteristics of malignant tumor, seriously affecting the quality of life of patients and threatening life. Therefore, studying colorectal cancer formation, controlling tumor metastasis and spread is the key to reduce the incidence of colorectal cancer, delay tumor progression and improve prognosis. For now, Tumor suppressor genes and metastasis suppressor genes influencing on the occurrence and prognosis of tumor is becoming a hot spot of research. Therefore, this study selected tumor suppressor gene Smad1 and metastasis suppressor gene Kiss-1 as indicators and used immunohistochemical streptavidin-biotin- peroxidase(SP) to detect expression of the two indicators in colorectal cancer, paraneoplastic normal tissue and colorectal adenoma tissues, then analyzed its clinical significance.Methods:1 Colorectal cancer tissues and normal tissues were from 49 cases of colorectal cancer patients in our hospital general who underwent surgery surgical resection(not received preoperative radiotherapy, chemotherapy) during from January in 2010 to January in 2013, 25 cases were male, 24 were females, mean age was 62.57 ± 11.20 years. Colorectal adenoma tissues were from 32 patients of endoscopy center in our hospital who underwent endoscopic resection during the same period, including 19 males and 13 females, mean age was 58.16 ± 11.03 years. The patients of each group were age and sex matched(all P>0.05). All subjects were confirmed by two independent chief physician in pathology department in our hospital to make a diagnosis, those with diagnosis consistent were included in the study. Groups: group of 49 cases with colorectal cancer(tumor tissues with surgery resection), normal control group of 49 patients(colorectal normal mucosa which was 5cm from the edge of the tumor tissue), group of 32 cases of colorectal adenomas(adenomas whose diameter ≥1cm with colonoscopic resection). Groups based on clinical and pathological features of colorectal cancer: 23 cases of colon cancer, 26 cases of rectal cancer, 7 cases of poorly differentiated adenocarcinoma, 42 cases of well-differentiated adenocarcinoma, 29 cases of I + II stages in TNM stage, 20 cases of III + IV stages, 31 cases without lymph node metastasis, 18 cases with lymph node metastasis.2 Routine histological processing: all specimens were fixed in 10% formalin solution, embedded in paraffin and sliced, HE staining was for pathological examination. Histological grade was according to TNM staging system of colorectal cancer formulated by the American Joint Committee on Cancer(AJCC) / International Union Against Cancer(UICC).3 Immunohistochemistry: tissues were paraffin-embedded and sliced continuously with 3.5um ~ 4um thickness, oven 60℃ ~ 65 ℃ overnight, dewaxed, citric repair liquid boiling to repair, used SP immunohistochemical staining according to immunohistochemistry kit manual steps strictly, colored with DAB, hematoxylin staining, known Kiss-1 protein or Smad1 protein positive slice as positive control, PBS was used instead of primary antibody as a negative control.4 Interpretation of the results: used double-blind method to observe results under a microscope. Kiss-1 protein or Smad1 protein is cytoplasmic staining, cytoplasm brown was positive, not coloring was negative. Positive determination was judged by positive cells and staining intensity.5 Statistical treatment: The experiment data were used by SPSS 16.0 software and analyzed by c2 test, P<0.05 was considered the difference was statistically significant.Results : 1 Expressions of Kiss-1 among three groups 1.1 Kiss-1 protein was pale yellow in colorectal cancer cell cytoplasm, weakly positive expression, Kiss-1 protein was yellow in colorectal adenoma cell cytoplasm, positive expression, Kiss-1 protein was brown in normal colorectal mucosa cell cytoplasm, strongly positive expression. The expression of Kiss-1 protein among colorectal cancer group, colorectal adenoma group and the control group was statistically significant(P<0.05). 1.2 Comparison between the two groups: the expression of Kiss-1 protein in colorectal cancer was significantly lower than colorectal adenoma group and the normal control group, the difference was statistically significant(P<0.05), There was no statistical significance between adenoma group and normal control group(P> 0.05). 1.3 Relations of Kiss-1 expression in colorectal cancer and its clinicopathological features: the expression of Kiss-1 in colorectal cancer was related with patients with lymph node metastasis and TNM staging(P<0.05), its expression in the patients without lymph node metastasis were significantly higher in patients with lymph node metastasis, in patients with clinical stage I + II were significantly higher than III + IV patients, but no relation with sex, age, tumor location, tumor size, degree of differentiation, histological type(P>0.05). 2 Expressions of Smad1 among three groups 2.1 Smad1 protein was pale yellow in colorectal cancer cell cytoplasm, weakly positive expression, Smad1 protein was yellow in colorectal adenoma cell cytoplasm, positive expression, Smad1 protein was brown in normal colorectal mucosa cell cytoplasm, strongly positive expression. The expression of Smad1 protein among colorectal cancer group, colorectal adenoma group and the control group was statistically significant(P<0.05). 2.2 Comparison between the two groups: the expression of Smad1 protein in colorectal cancer was significantly lower than colorectal adenoma group and the normal control group, the difference was statistically significant(P<0.05), There was no statistical significance between adenoma group and normal control group(P> 0.05). 2.3 Relations of Smad1 expression in colorectal cancer and its clinicopathological features: the expression of Smad1 in colorectal cancer was no related with patients with sex, age, tumor location, tumor size, degree of differentiation, histological type, lymph node metastasis and TNM staging(P>0.05).Conclusions:1 The expression of Kiss-1 protein in colorectal cancer was significantly lower than colorectal adenoma group and the normal control group, suggesting that Kiss-1 protein expression was down-regulated in the occurrence of colorectal cancer, playing a role of tumor suppressor.2 Divide colorectal cancer patients into several groups according to clinical and pathological features, expression of Kiss-1 protein in group without lymph node metastasis was significantly higher than group with lymph node metastasis, group with Stage I and Stage II was higher than group with Stage III and Stage IV, suggesting that Kiss-1 protein plays the role of inhibiting metastasis of tumor in the development of colorectal cancer, its expression might be useful in formulating clinical individual treatment and evaluating prognosis.3 The expression of Smad1 protein in colorectal cancer was significantly lower than colorectal adenoma group and the normal control group, suggesting that Smad1 protein expression was down-regulated in normal colon epithelial malignant transformation process, Samd1 gene may be similar to the tumor suppressor gene in the pathogenesis of colorectal cancer.4 The expression of Kiss-1 protein and Smad1 protein colorectal adenoma group was no difference with the control group, suggesting that Kiss-1 protein and Smad1 protein abnormalities may not be an early event in colorectal cancer. |
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