Walch A, Specht K, Bink K, Zitzelsberger H, Braselmann H, Bauer M, Aubele M, Stein H, Siewert J R, Höfler H, Werner M
Institute of Pathology, and Department of Surgery, Technische Universität München, Munich, Germany.
Lab Invest. 2001 Jun;81(6):791-801. doi: 10.1038/labinvest.3780289.
The importance of alterations of the Her-2/neu oncogene in the tumorigenesis of Barrett's adenocarcinoma (BCA) is discussed controversially. In the present study, we evaluated for the first time the Her-2/neu status in the metaplasia-dysplasia-adenocarcinoma sequence of BCA simultaneously at the DNA, mRNA, and protein level using resection specimens of 25 patients. The locus-specific Her-2/neu gene status was quantified by performing fluorescence in situ hybridization, and information about the ploidy status of chromosome 17 was obtained. Tissue sections from the same areas were used for quantitative RT-PCR (TaqMan RT-PCR) of laser-microdissected tumor cells and for immunohistochemistry to quantify Her-2/neu mRNA and oncoprotein expression. Her-2/neu gene amplification was observed in 35% of BCA, and all of these samples showed strong overexpression of both mRNA and oncoprotein. A polysomy 17 without Her-2/neu gene amplification was observed in 52% of BCA, showing a normal or moderately elevated mRNA expression and no or weak immunopositivity. From 13 areas of high-grade dysplasia (HGD) we found four to be amplified for the Her-2/neu locus, whereas five showed a polysomy 17. All four samples of HGD areas with Her-2/neu gene amplification displayed mRNA and strong oncoprotein overexpression; however, lower mRNA levels were seen than in the amplified BCA areas. None of the samples with low-grade dysplasia (LGD) showed a locus-specific Her-2/neu amplification, but polysomy 17 was present in four of eight cases. No changes were detected in BCA-associated intestinal metaplasia and squamous epithelium. In summary, only a locus-specific Her-2/neu gene amplification was associated with strong mRNA overexpression and strong membranous Her-2/neu immunostaining in BCA and HGD. A chromosome 17 polysomy, as found in the majority of BCA, led to no or weak mRNA overexpression and no or weak immunopositivity. In the metaplasia-dysplasia-adenocarcinoma sequence, a chromosome 17 polysomy without Her-2/neu gene amplification was already present in LGD. This may be a result of an early polyploidization, preceding the later genetic events, such as Her-2/neu gene amplification in HGD and BCA.
关于Her-2/neu癌基因改变在巴雷特腺癌（BCA）肿瘤发生中的重要性存在争议。在本研究中，我们首次使用25例患者的手术切除标本，在DNA、mRNA和蛋白质水平同时评估了BCA化生-发育异常-腺癌序列中的Her-2/neu状态。通过荧光原位杂交对位点特异性Her-2/neu基因状态进行定量，并获得有关17号染色体倍性状态的信息。来自相同区域的组织切片用于激光显微切割肿瘤细胞的定量逆转录聚合酶链反应（TaqMan RT-PCR）以及免疫组织化学，以定量Her-2/neu mRNA和癌蛋白表达。在35%的BCA中观察到Her-2/neu基因扩增，所有这些样本均显示mRNA和癌蛋白的强烈过表达。在52%的BCA中观察到无Her-2/neu基因扩增的17号染色体多体性，显示mRNA表达正常或中度升高，且无免疫阳性或免疫阳性较弱。在13个高级别发育异常（HGD）区域中，我们发现4个区域的Her-2/neu位点扩增，而5个区域显示17号染色体多体性。所有4个Her-2/neu基因扩增的HGD区域样本均显示mRNA和强烈的癌蛋白过表达；然而，与扩增的BCA区域相比，mRNA水平较低。低级别发育异常（LGD）的样本均未显示位点特异性Her-2/neu扩增，但8例中有4例存在17号染色体多体性。在BCA相关的肠化生和鳞状上皮中未检测到变化。总之，在BCA和HGD中，只有位点特异性Her-2/neu基因扩增与强烈的mRNA过表达和强烈的膜性Her-2/neu免疫染色相关。如在大多数BCA中发现的17号染色体多体性，导致无mRNA过表达或过表达较弱，且无免疫阳性或免疫阳性较弱。在化生-发育异常-腺癌序列中，LGD中已存在无Her-2/neu基因扩增的17号染色体多体性。这可能是早期多倍体化的结果，早于后期的遗传事件，如HGD和BCA中的Her-2/neu基因扩增。
