Tampanaru-Sarmesiu A, Stefaneanu L, Thapar K, Kontogeorgos G, Sumi T, Kovacs K
Department of Laboratory Medicine, St. Michael's Hospital, University of Toronto, Ontario, Canada.
Am J Pathol. 1998 Feb;152(2):413-22.
Transferrin (Tf), a major transport protein for iron in the blood and an essential growth factor in some tissues, acts via specific transferrin receptor (TfR). We studied the cellular distribution of Tf and TfR gene expression in 50 human nontumorous autopsy pituitaries and 42 surgically removed pituitary adenomas. Tf and TfR mRNA accumulation was correlated with Ki-67 proliferation marker. In nontumorous pituitaries without iron deposits Tf immunoreactivity was localized in some growth hormone, prolactin, adrenocorticotropin, thyrotropin, and luteinizing hormone cells. Most adenohypophysial cells were immunopositive for TfR. In pituitaries with iron deposits, Tf and TfR were localized only in iron-free cells. Tf mRNA and protein were present in 27 and 32 adenomas, respectively; Ki-67 labeling index of tumors positive for Tf mRNA was significantly higher than in those without transcript (0.94% versus 0.51%; P < 0.025). A positive linear correlation between tumor growth fraction and Tf mRNA signal intensity was evident (r = 0.32; P = 0.04). TfR mRNA and encoded protein were demonstrated in 26 and 31 adenomas, respectively; Ki-67 immunoreactivities were not correlated with the presence of TfR transcripts and signal intensities. These data suggest that Tf may act as a growth-promoting factor for pituitary tumors.
转铁蛋白（Tf）是血液中主要的铁转运蛋白，也是某些组织中必需的生长因子，它通过特异性转铁蛋白受体（TfR）发挥作用。我们研究了50例人类非肿瘤性尸检垂体和42例手术切除的垂体腺瘤中转铁蛋白和转铁蛋白受体基因表达的细胞分布。转铁蛋白和转铁蛋白受体mRNA的积累与Ki-67增殖标志物相关。在无铁沉积的非肿瘤性垂体中，转铁蛋白免疫反应定位于一些生长激素、催乳素、促肾上腺皮质激素、促甲状腺激素和黄体生成素细胞。大多数腺垂体细胞转铁蛋白受体免疫阳性。在有铁沉积的垂体中，转铁蛋白和转铁蛋白受体仅定位于无铁细胞。转铁蛋白mRNA和蛋白分别存在于27例和32例腺瘤中；转铁蛋白mRNA阳性肿瘤的Ki-67标记指数显著高于无转录本的肿瘤（0.94%对0.51%；P<0.025）。肿瘤生长分数与转铁蛋白mRNA信号强度之间存在明显的正线性相关（r=0.32；P=0.04）。转铁蛋白受体mRNA和编码蛋白分别在26例和31例腺瘤中得到证实；Ki-67免疫反应性与转铁蛋白受体转录本的存在和信号强度无关。这些数据表明，转铁蛋白可能作为垂体肿瘤的生长促进因子。
