Wong S Y, Purdie A T, Han P
Department of Pathology, National University of Singapore, National University Hospital.
Am J Pathol. 1992 Jun;140(6):1473-82.
Thrombospondin (TSP), which plays an important hemostatic role, is a 450-kd cytoadhesive protein present in the alpha granules of platelets. In vitro experiments using cultured malignant cells suggest that it may help to mediate malignant cell attachment to extracellular matrix and may be important in cancer invasiveness. The authors studied a group of malignant and benign breast tissues for the expression of TSP and provide evidence that TSP may have a role in tumor invasiveness. Using immunohistochemical techniques, the authors found in 48 fresh specimens of breast carcinoma that TSP stained strongly in the desmoplastic stroma or at the basement membrane associated with the malignant ductal epithelium. Tumor cells abutting these tissues revealed cytoplasmic staining for TSP. Stronger TSP staining was seen in the poorly differentiated tumors. These findings were compared with those of normal and benign breast tissue, which showed no TSP staining apart from reactivity in the large distended cysts of fibrocystic disease and faint staining in the stroma of fibroadenomas. Staining for integrin was positive in lymphocytes of both malignant and benign breast disease and equivocally also in the stromal cells of the breast cancer tissue. Immunoreactivity to TSP in tissues was also compared with that of fibronectin, laminin, and collagen type I, III, and IV. The overall findings suggest that thrombospondin may have a role in the tumor biology of invasiveness.
血小板反应蛋白（TSP）是一种存在于血小板α颗粒中的450千道尔顿细胞粘附蛋白，在止血过程中发挥重要作用。利用培养的恶性细胞进行的体外实验表明，它可能有助于介导恶性细胞与细胞外基质的附着，并且在癌症侵袭过程中可能起重要作用。作者研究了一组恶性和良性乳腺组织中TSP的表达情况，并提供证据表明TSP可能在肿瘤侵袭中发挥作用。通过免疫组化技术，作者在48例新鲜乳腺癌标本中发现，TSP在促结缔组织增生性基质或与恶性导管上皮相关的基底膜处强烈染色。毗邻这些组织的肿瘤细胞显示TSPSP的细胞质中有TSP染色。在低分化肿瘤中可见更强的TSP染色。这些发现与正常和良性乳腺组织的情况进行了比较，正常和良性乳腺组织除了在纤维囊性疾病的大扩张囊肿中有反应以及在纤维腺瘤的基质中有微弱染色外，均未显示TSP染色。整合素染色在恶性和良性乳腺疾病的淋巴细胞中均为阳性，在乳腺癌组织的基质细胞中也有不明确的阳性。还将组织中TSP的免疫反应性与纤连蛋白、层粘连蛋白以及I、III和IV型胶原蛋白的免疫反应性进行了比较。总体研究结果表明，血小板反应蛋白可能在肿瘤侵袭生物学中发挥作用。
