显微数字成像组合组织芯片技术平台的建立及其在肿瘤标志物研究中的应用

目的:利用我室新建立的显微数字成像组合组织芯片技术平台探讨新型肿瘤标志物MDA-7/IL-24在胃癌中的表达及意义。方法:取胃癌标本50例及对应正常胃黏膜10例,从预先作好标记的供体石蜡块中取出目标组织,应用组织芯片点样仪制成一定阵列的受体石蜡块,将石蜡切片贴附于硅胶包被的玻片上,采用高敏感EnVision两步法进行MDA-7/IL-24单克隆抗体免疫组织化学染色。将染好的切片置于显微数字成像分析仪中读取图像信息并进行分析。结果:计算机软件将读取的组织芯片全貌显示在屏幕上,研究者在计算机定位下对每一标本点逐一放大分析。50例胃癌组织标本中,剔除组织脱落或取材部位欠佳的无效点,42例纳入统计分析。42例胃癌中27例MDA-7/IL-24表达消失(64.29%)。10例正常胃黏膜腺体细胞质MDA-7/IL-24染色全部阳性。MDA-7/IL-24表达消失组癌周淋巴结转移率明显增高(P=0.01),且在TNMⅢ、Ⅳ期患者明显多于TNMⅠ、Ⅱ期(P=0.003)。MDA-7/IL-24表达与否与年龄、性别、肿瘤发生部位及组织分型无明显关系。结论:显微数字成像组合组织芯片技术在筛查肿瘤标志物表达时显示出高通量、可比性强、计算机定位精确及图像清晰直观等优点,是后基因组时代大规模肿瘤标志物筛选定位分析中可以选择的一种新型技术平台。MDA-7/IL-24表达消失与胃癌的浸润生长及淋巴结转移增加有明显关系,故可将MDA-7/IL-24表达消失作为判断胃癌浸润、转移能力的一种新型肿瘤标志物。

A new platform and its utilization of tissue array/digital microscopic imaging system in screening the tumor marker

Objective To explore the expression and significance of MDA-7/IL-24, a new tumor marker in gastric carcinoma, by the newly established tissue array/ digital microscopic imaging system. Methods A total of 50 gastric carcinoma samples and 10 normal gastric mucosa samples were collected. Routine HE staining slides were made for morphological observation. The target tissues from the donor paraffin block were picked up and the tissues were arranged as an array in the recipient block on tissue array instrument. Immunohistochemical method was used to detect the expression of MDA-7/IL-24 by the high sensitive EnVision two steps. The stained slides were inserted into the slide-reading driver of digital microscopic imaging system for image information analysis. Results The computer captured the whole image information on the screen. Then the samples were analyzed one by one at high-power magnification without the disadvantage of omitting some points under the routine microscope. Forty-two samples of gastric cancer were enrolled in the final analysis after excluding 8 samples for some drop-off points or poorly-sampled points. The expression of MDA-7/IL-24 disappeared in 27 out of 42 samples (64.29%). All of the normal gastric mucosa glands were positive for MDA-7/IL-24. The disappearance of MDA-7/IL-24 expression was closely related with the metastasis of lymph nodes (P=0.01) and the TNM staging (P=0.003). There was no relationship between the MDA-7/IL-24 expression with the age, gender, tumor location or histological classification. Conclusions Tissue array/ digital microscopic imaging system has significant advantages in the high-throughput, highly-controlled conditions and the delicate image.And it is a novel technical platform for widespread gene expression screening in the post-genomic era. MDA-7/IL-24 has the feature of tumor suppressor in gastric carcinoma. The disappearance of MDA-7/IL-24 expression may be a predictor for metastasis and aggressive ability of gastric carcinoma.