大肠癌CD24的表达及其与肿瘤细胞增殖和血管形成的关系

Expression of CD24 and its relationship with angiogenesis and tumor cell proliferation in colorectal carcinoma

目的:探讨CD24在大肠癌中的表达及其与细胞增殖、血管生成的关系.方法:运用流式细胞术直接免疫荧光法检测66例大肠癌肿瘤组织及相应正常大肠黏膜CD24的表达量.CD24蛋白表达量以阳性率(PPC)和平均荧光强度MFI值表示.运用免疫组织化学法检测肿瘤组织CD34,PCNA的表达情况,根据CD34的染色情况计算出大肠癌组织的微血管密度(microvessel density),根据PCNA染色情况计算出肿瘤细PCNA标记指数.结果:大肠癌肿瘤组织CD24阳性率90.40%(75.10%-96.35%)明显高于相应的癌旁组织36.15%(32.00%-53.28%)(χ2=6.877,P<0.001).大肠癌肿瘤组织CD24蛋白MFI值18.10(11.45-25.43),明显高于正常黏膜组织8.41(5.59-10.33)(χ2=6.934,P<0.001).浸润型、高Dukes分期、高pTNM分期及有淋巴结转移的癌组织中CD24蛋白的平均荧光强度显著高于对应组(P<0.05).浸润型、低分化、高Dukes分期、高pTNM分期及有淋巴结转移的癌组织中CD24蛋白阳性百分率显著高于对应组(P<0.05).在CD24阳性表达病例中,PCNA的表达随着CD24表达强度的升高而升高(P<0.05).大肠腺癌肿瘤细胞CD24阳性表达率与MVD呈正相关(r=0.243,P=0.050).而CD24蛋白平均荧光强度与MVD未见明显相关(r=0.115,P=0.358).结论:CD24在大肠腺癌中表达水平明显上调,并与肿瘤细胞增殖、血管生成密切相关.

AIM： To investigate the expression of CD24 and its role in the angiogenesis and tumor cell proliferation in colorectal carcinoma. METHODS： Direct immunofluorescence flow cytometry （FCM） was used to detect the expression of CD24 in 66 specimens of colorectal carcinoma and normal colorectal tissues. The expression of CD24 protein was shown by the percentage of positive cells （PPC） and mean fluorescence index （MFI）, The expression of CD34 and proliferating cell nuclear antigen （PCNA） in colorectal carcinoma were detected by immunohistochemistry, Microvessel density （MVD） was figured out according to the positive staining for CD34, The proliferation index of carcinoma cells was figured out according to the expression of PCNA. RESULTS： The values of PPC and MFI were significantly higher in colorectal carcinoma tissue than that in the normal colorectal tissue （PPC： 90.40% vs 36.15%, X2 = 6.877, P 〈 0.001; MFI： 18.10 vs 8.41,χ^2 = 6.934, P 〈 0.001）. The values of MFI and PPC were significantly correlated with tumor stages （Dukes and pTNM）, lymph noda metastasis and infiltration types （P 〈 0.05）. The expression of PCNA was increased with the upregulation of CD24 expression in CD24-positive cases （P 〈 0.05）. There was a significant correlation between the positive rate of CD24 expression and the value of MVD in colorectal carcinoma （r = 0.243, P = 0.050）. But the value of MFI had no marked correlation with that of MVD in colorectal carcinoma （r = 0.115, P = 0.358）. CONCLUSION： CD24 expression is obviously up-regulated in colorectal carcinoma, and it is correlated with the angiogenesis of tumor tissues and proliferation of tumor cells.