Tauchi K, Tsutsumi Y, Hori S, Yoshimura S, Osamura R Y, Watanabe K
Department of Pathology, Tokai University School of Medicine, Kanagawa.
Jpn J Clin Oncol. 1991 Aug;21(4):256-63.
The major heat shock protein, HSP70, protects cells from a variety of stressful stimuli, while c-myc protein allegedly stimulates the expression of HSP70 by transacting on the HSP70 promotor. The present study was aimed at correlating the expression of HSP70 with that of c-myc protein in benign and malignant breast lesions. Indirect immunoperoxidase and immunoblotting techniques using monoclonal antibodies were employed. Fresh frozen sections were prepared from five fibroadenomas and 59 breast carcinomas. Immunohistochemically, both substances were localized in the nuclei and/or cytoplasm of normal and neoplastic epithelial cells. The stromal cells were positive for c-myc protein but negative for HSP70. The expressions of HSP70 and c-myc protein were comparable to each other in the malignant cells from 37 (63%) carcinomas. In 17 (29%) carcinomas, c-myc protein expression predominated over that of HSP70, whereas in five (8%) carcinomas, HSP70 was predominant. Carcinomas with high-grade nuclear atypia often showed negative HSP70 staining, whereas tumors with nuclear HSP70 localization tended to accompany lower-grade nuclear atypia. A similar relation was also observed between c-myc protein expression and nuclear atypia of the tumor. All five fibroadenomas and most of the non-neoplastic epithelial cells adjacent to cancer showed strong reactivities with both substances. Immunoblot analysis for HSP70 revealed a clear, single band in the extract of tumors with strong HSP70 staining, but no, or only faint, bands were seen in the extract of immunohistochemically HSP70-negative carcinomas. The discrepancy between the expressions of each substance in a certain percentage of breast carcinomas may suggest the presence of HSP70 production mechanisms other than the c-myc protein-triggered promotor pathway.
主要热休克蛋白HSP70可保护细胞免受各种应激刺激，而c-myc蛋白据称可通过作用于HSP70启动子来刺激HSP70的表达。本研究旨在探讨良性和恶性乳腺病变中HSP70的表达与c-myc蛋白表达之间的相关性。采用了使用单克隆抗体的间接免疫过氧化物酶和免疫印迹技术。从5个纤维腺瘤和59个乳腺癌中制备新鲜冰冻切片。免疫组织化学显示，这两种物质均定位于正常和肿瘤上皮细胞的细胞核和/或细胞质中。基质细胞c-myc蛋白呈阳性，但HSP70呈阴性。在37例（63%）癌的恶性细胞中，HSP70和c-myc蛋白的表达相当。在17例（29%）癌中，c-myc蛋白表达高于HSP70，而在5例（8%）癌中，HSP70占主导。核异型性高的癌通常HSP70染色阴性，而细胞核中存在HSP70的肿瘤往往伴有较低级别的核异型性。在c-myc蛋白表达与肿瘤核异型性之间也观察到类似关系。所有5个纤维腺瘤以及大多数与癌相邻的非肿瘤上皮细胞对这两种物质均表现出强烈反应。对HSP70的免疫印迹分析显示，HSP70染色强的肿瘤提取物中有一条清晰的单带，而免疫组织化学HSP70阴性的癌提取物中未见条带或只有 faint条带。在一定比例的乳腺癌中，每种物质表达之间的差异可能表明存在c-myc蛋白触发的启动子途径以外的HSP70产生机制。
