Stefanou D G, Nonni A V, Kalpouzos G, Evangelou A, Agnantis N J
Department of Pathology, University of Ioannina, Medical School, Greece.
In Vivo. 1998 Sep-Oct;12(5):511-21.
This study was designed to identify the immunophenotypic characteristics of malignant soft tissue tumours, induced experimentally with benzo(a)pyrene (BaP), and to evaluate the immunohistochemical expression of the ras oncogene family and p53 onco-suppressor gene in these tumours, in association with prognostic factors. Seventy-five male Wistar rats were subcutaneous injected, dorsally, with a single dose of 10.08 mgr BaP. A solid, well-circumscribed tumour was formed at the injection site, in 70 of the animals, 80-100 days after the carcinogen's administration. The tumour as well as selected main organs were excised and studied after the animals' death. All the specimens were fixed in formalin 10%, embedded in paraffin and stained with H + E. The immunohistochemical avidin-biotin method was performed in the tumour sections, using the following monoclonal or polyclonal antibodies: vimentin, desmin, muscle specific actin (MSA), a-smooth muscle actin (SMA), myoglobin, smooth muscle myosin, a-1-antitrypsin, a-1-antichymotrypsin, S-100 protein, epithelial membrane antigen (EMA), K-ras, H-ras, Pan-ras and p53. The induced tumours of the animals were almost well-circumscribed, with a partly storiform cut surface. Histologically, their appearance was more conventional with high grade leiomyosarcomas; about half of them showed highly anaplastic areas, resembling other pleomorphic undifferentiated sarcomas. Pulmonary metastatic foci were detected in 37 animals. Immunohistochemically, all the tumours displayed positive expression of vimentin, MSA and SMA. Desmin was positively expressed in 40 tumours, smooth muscle myosin in 57 tumours and EMA in 12 tumours. All the tumours were negative for myoglobin, a-1-antitrypsin, a-1-antichymotrypsin and S-100 protein. In addition, five tumours showed a positive reaction for K-ras p21, 37 for H-ras p21, 41 for Pan-ras p21 and 14 for p53 protein. The overexpression of the oncoproteins H-ras p21 and Pan-ras p21 in these tumours was significantly associated with a non-advanced tumour stage (absence of metastatic focus). In conclusion, the histological as well as the immunophenotypic features of the induced tumours are more conventional with leiomyosarcomas mostly of high grade; many of them are "dedifferentiated". The identification of both ras and p53 gene products in these tumours indicates that alterations of these genes are common but not specific events, implicated in the tumourigenesis, which may become prognostic markers for this subtype of soft tissue sarcomas.
本研究旨在确定经苯并(a)芘（BaP）实验诱导产生的恶性软组织肿瘤的免疫表型特征，并评估这些肿瘤中ras癌基因家族和p53抑癌基因的免疫组化表达，以及与预后因素的相关性。75只雄性Wistar大鼠背部皮下注射单剂量10.08毫克的BaP。在给予致癌物后80 - 100天，70只动物的注射部位形成了一个边界清晰的实性肿瘤。动物死亡后，切除肿瘤及选定的主要器官进行研究。所有标本均用10%福尔马林固定，石蜡包埋，苏木精和伊红（H + E）染色。在肿瘤切片上采用免疫组化抗生物素蛋白-生物素方法，使用以下单克隆或多克隆抗体：波形蛋白、结蛋白、肌肉特异性肌动蛋白（MSA）、α-平滑肌肌动蛋白（SMA）、肌红蛋白、平滑肌肌球蛋白、α-1-抗胰蛋白酶、α-1-抗糜蛋白酶、S-100蛋白、上皮膜抗原（EMA）、K-ras、H-ras、泛ras和p53。动物诱导产生的肿瘤几乎边界清晰，部分切面呈束状。组织学上，其表现更符合高分级平滑肌肉瘤；约一半肿瘤显示高度间变区域，类似于其他多形性未分化肉瘤。在37只动物中检测到肺转移灶。免疫组化方面，所有肿瘤均显示波形蛋白、MSA和SMA阳性表达。40个肿瘤结蛋白呈阳性表达，57个肿瘤平滑肌肌球蛋白呈阳性表达，12个肿瘤EMA呈阳性表达。所有肿瘤肌红蛋白、α-1-抗胰蛋白酶、α-1-抗糜蛋白酶和S-100蛋白均为阴性。此外，5个肿瘤K-ras p21呈阳性反应，37个肿瘤H-ras p21呈阳性反应，41个肿瘤泛ras p21呈阳性反应，14个肿瘤p53蛋白呈阳性反应。这些肿瘤中癌蛋白H-ras p21和泛ras p21的过表达与肿瘤非进展期（无转移灶）显著相关。总之，诱导产生的肿瘤的组织学及免疫表型特征更符合大多为高分级的平滑肌肉瘤；其中许多是“去分化的”。这些肿瘤中ras和p53基因产物的鉴定表明，这些基因的改变是常见但非特异性事件，与肿瘤发生有关，可能成为这种软组织肉瘤亚型的预后标志物。
