Objective: To investigate the expression of claudin-3 in colorectal carcinoma and its association with the occurrence, progression and prognosis of colorectal cancer.
Methods: Forty surgical specimens of colorectal carcinoma and 22 adjacent normal tissues resected between October, 2010 and January, 2013 at Nanfang Hospital were examined for claudin-3 expression using immunohistochemistry, which was analyzed in association with the clinicopathological parameters and the survival of the patients.
Results: Claudin-3 was expressed mainly on the cell membrane, and its positivity rate was significantly higher in cancer tissues than in normal tissues (92.50% vs 59.09%, P<0.05). In 13 cases claudin-3 expression was detected in both the cancer tissues and adjacent normal tissues with average expression scores of 4.538 and 3.269, respectively (P<0.05). In the cancer tissues, the strongly positive expression rate was significantly higher in poorly differentiated tissues (85.71%) than in well (21.43%) and moderately (36.48%) differentiated tissues (P<0.05), and was higher in cases with lymph node metastasis than in those without (61.11% vs 22.72%, P<0.05). The strongly positive expression rate of claudin-3 was not correlated with the patients'age, gender, tumor location or tumor size (P>0.05). Of the 33 cancer patients followed up, 14 had a postoperative survival time no longer than 3 years and 19 had longer survival time, and their average expression scores differed significantly (4.50 vs 3.526, P<0.05).
Conclusion: Claudin-3 is over-expressed in colorectal cancer tissues, and its high expression may promote the occurrence and progression of colorectal cancer. Claudin-3 may serve as a molecular biomarker for early diagnosis and prognostic evaluation.
目的: 观察在结直肠癌组织中紧密连接蛋白claudin-3的表达，探讨claudin-3与结直肠癌发生、发展、转移及预后的关系。方法收集南方医院2010年10月~2013年1月间手术切除结直肠癌组织40例（癌组）及癌旁正常结直肠粘膜组织22例（癌旁正常组）。应用免疫组化法检测组织中claudin-3的表达水平。分析和比较癌组不同病理参数和不同存活情况病例间的claudin-3蛋白表达情况。
结果: claudin-3蛋白的表达主要分布在细胞膜上。癌组阳性表达率为92.50%，显著高于癌旁正常组的59.09%（P < 0.05）。13例来自同一患者的癌组织和癌旁正常组织的claudin-3表达平均评分（染色强度评分+阳性细胞所占比例评分）分别为4.538和3.269（P=0.019）。在40例癌组患者中，高分化组、中分化组、低分化组claudin-3的强阳性表达率分别为21.43%、36.84%和85.71%，其中高分化组与低分化组间及低分化组与中分化组间的差异均有统计学意义（P < 0.05）；淋巴结转移组claudin-3强阳性率为61.11%，显著高于无淋巴结转移组的22.72%（P < 0.05）；在不同年龄、性别、肿瘤部位、肿瘤最长径的分组间，claudin-3强阳性表达率差异均无统计学意义（P>0.05）。随访癌组的40例患者，失访7例，术后生存期≤3年14例（死亡组），生存期>3年19例（存活组），两组claudin-3表达平均评分分别为4.50和3.526（P < 0.05）。
结论: 结直肠癌组织中claudin-3的表达显著升高，claudin-3的高强度表达可能促进了结直肠癌的发生及发展过程，并可能成为结直肠癌早期诊断及判断预后的分子生物学指标。