结直肠癌组织抑癌基因PTEN和癌基因C-myc蛋白表达及其相关性

目的：探讨抑癌基因PTEN和癌基因C-myc在结直肠癌发生、发展中的作用及其相关性。 方法：采用免疫组织化学链霉菌抗生物素蛋白-过氧化酶法（S-P法），检测60例结直肠癌组织、10例癌旁组织及8例正常结直肠黏膜中PTEN和C-myc蛋白表达。 结果：结直肠癌组织中，C-myc蛋白表达阳性率为76.70%（46/60），显著高于正常（0）及邻近结直肠(癌旁)组织（10%），组间比较差异均有显著性（P<0.01）；C-myc蛋白过度表达与结直肠癌肝转移呈正相关关系（r＝5.540，P<0.05），与TNM分期无相关性（r＝0.013，P>0.05）；结直肠癌组织中，PTEN蛋白表达阳性率为25.00%(15/60)，显著低于正常（100%）及邻近结直肠(癌旁)组织（90%）（P<0.01）；PTEN蛋白表达与肿瘤分化程度呈正相关（r＝0.869，P<0.05），与TNM分期、淋巴结转移和肝转移均呈负相关（r＝－0.791，r＝－0.741，r＝－0.634，P<0.05）；C-myc蛋白表达与PTEN蛋白表达水平呈负相关（r＝－0.322，P<0.001）。 结论：癌基因C-myc蛋白过度表达不能作为判断结直肠癌肿瘤状态的单独指标；抑癌基因PTEN蛋白的表达缺失在结直肠癌的发生、发展及转移过程中起促进作用，有望成为结直肠癌诊断和预后判断的标记物。

Correlation between expressions of PTEN and C-myc in colorectal carcinoma

Objective To investigate the correlation between the expressions of tumour suppressor gene PTEN and oncogene C-myc in colorectal carcinoma.Methods The expressions of PTEN and C-myc protein in normal colorectal mucosa(n=8), adjacent non-cancerous tissues(n=10) and primary colorectal carcinoma tissues(n=60) were observed by S-P immunohistochemical assay.Results Of 60 colorectal carcinoma tissues,C-myc protein was detected in 46 cases.The expression rate of C-myc in the primary colorectal carcinoma tissues(76.70%) was significantly higher than that in the normal(0) and adjacent non-cancerous tissues(10%)(P<0.01).Overexpression of C-myc was significantly correlated with hepatic metastasis(r=5.540,P<0.05) and was not related with TNM staging(r=0.013,P>0.05).The positive expression rate of PTEN protein in the primary colorectal carcinoma tissues(25.00%,15/60) was significantly lower than that in the normal(100%) and adjacent non-cancerous tissues(90%)(P<0.01).PTEN protein expression was positively correlated with pathological differentiational degree(r=0.869,P<0.05),negatively with TNM staging,lymph nodes metastasis and hepatic metastasis(r=0.791,r=-0.741,r=-0.634,P<0.05).The level of C-myc protein expression was negatively correlated with PTEN expression(r=-0.322,P<0.001).Conclusion Cmyc protein overexpression can not be used as a clinicopathological parameter to dignose colorectal cancer.The expression of PTEN is closely related to clinicopathological features in colorectal carcinoma,and could be used as a marker of tumour burden of colorectal carcinoma.