Iwanij V, Hull B E, Jamieson J D
J Cell Biol. 1982 Dec;95(3):727-33. doi: 10.1083/jcb.95.3.727.
A transplantable acinar cell tumor of the rat pancreas has been examined by light and electron microscopy. The tumor cells, though highly cytodifferentiated and characterized by the presence of abundant rough-surfaced endoplasmic reticulum, elements of the Golgi complex, and zymogen granules, undergo mitosis in a manner similar to that seen in the developing pancreas. Cells in the parenchyma of the tumor grow as disarrayed cords and sheets, are randomly oriented with respect to each other, and do not form acinar structures. However, when in contact with the adventitial surface of blood vessels, the tumor cells palisade and form a polarized layer of cells with their zymogen granule-rich poles oriented away from the vessel lumen. Only in this area of the tumor is a basal lamina present that underlies the basal plasmalemma of the reoriented epithelial cells. Freeze-fracture electron microscopy of tumor cells in the parenchyma shows extensive disruption of tight junctions whose sealing strands are randomly distributed over the entire plasmalemma. Gap junctions are infrequent and when present are often enclosed by tight-junctional strands. Intramembrane particles are randomly distributed over the cell surface. Both the absence of basal lamina and derangement of the junctional complexes may account in part for the altered morphogenesis of this tumor.
通过光学显微镜和电子显微镜对大鼠胰腺的一种可移植腺泡细胞瘤进行了检查。肿瘤细胞虽然高度细胞分化，其特征是存在丰富的糙面内质网、高尔基体成分和酶原颗粒，但以与发育中的胰腺相似的方式进行有丝分裂。肿瘤实质中的细胞呈杂乱的索状和片状生长，彼此随机排列，不形成腺泡结构。然而，当与血管的外膜表面接触时，肿瘤细胞呈栅栏状排列，并形成一层极化的细胞层，其富含酶原颗粒的极远离血管腔。只有在肿瘤的这个区域才有基膜，它位于重新定向的上皮细胞的基底质膜之下。对实质中肿瘤细胞的冷冻断裂电子显微镜检查显示紧密连接广泛破坏，其封闭索随机分布在整个质膜上。间隙连接很少见，如果存在，通常被紧密连接索包围。膜内颗粒随机分布在细胞表面。基膜的缺失和连接复合体的紊乱可能部分解释了这种肿瘤形态发生的改变。
