Investigation of stam cells in experimental salivary gland carcinogenesis. (Immunohistochemical evaruation for oncogene product)

研究了含DMBA海绵颗粒植入大鼠颌下腺（SMGs）及导管结扎后的增殖细胞及其免疫组化特性。在正常大鼠SMGs中，增殖细胞非常少，表皮生长因子（EGF）局限于颗粒曲小管（GCT）中的颗粒，GCT的柱状细胞和过渡细胞以及纹状管（SD）和排泄管（ED）中存在S-100 α， SD和ED中存在K8.12角蛋白、碱性成纤维细胞生长因子（bFGF）和c-erbB-2癌蛋白，层粘连蛋白存在于腺上皮基底膜和血管中。DMBA/海绵植入2 ~ 3周后，DMBA/海绵周围坏死水肿区可见小簇增生细胞，坏死水肿周围炎症区可见导管样结构及导管段扩张，可见少量增生细胞（10 ~ 25%）。这些成分对K8.12角蛋白、S-100 α蛋白、bFGF和c-erbB-2癌蛋白呈阳性，对EGF呈阴性。DMBA/海绵植入后4 ~ 6周，角化上皮像囊肿一样在DMBA/海绵周围延伸，囊性上皮基底区和旁基底区可见增殖细胞（* 27%）。囊性上皮的组织学和免疫组织化学特征与口腔白斑相似，在该病变中观察到c-erbB-2癌蛋白。DMBA/海绵植入后8 - 12周出现鳞状细胞癌（SCC）。增殖细胞主要分布在SCC的基底区和旁基底区，增殖细胞的发生率均在30%以上。在SCC中也观察到C-erbB-2癌蛋白。12周后，肿瘤细胞出现侵袭性生长，基底膜破裂。在导管结扎的SMG中，增殖细胞在导管样结构中增加，在实验第3天PCNA标记的峰值约为50%，在实验第21天逐渐下降到10%。导管结扎的SMG的组织学和免疫组织化学结果与癌变过程中出现的导管样结构相似。实验动物未结扎腺体中腺泡细胞有增殖活性，第2天达到峰值（* 20%），第10天迅速降至正常水平。这些结果表明，在SMG分泌功能加速的情况下，分泌细胞可能会增殖，以适应功能。然而，在受到损伤的情况下，导管节段具有更大的增殖潜力，这些细胞可能是腺体再生的主要参与细胞，并可能是大多数唾液腺肿瘤组织发生的来源。此外，c-erbB-2癌蛋白在导管段和肿瘤细胞中出现，EGF在GCT中积累，这些发现可能与其他器官相比影响了快速癌变。少

Proliferating cells and its immunohistochemical properties were evaluated during experimental carcinogenesis induced by DMBA containing sponge-pellet implantation and after duct-ligation of rat submandibular glands (SMGs).In the normal rat SMGs, proliferating cells were very very few, epidermal growth factor (EGF) was confined to the granules in granular convoluted tubules (GCTs), S-100 alpha was found in pillar and transition cells in GCT and striated duct (SD) and excretory duct (ED), K8.12 keratin, basic fibroblast growth factor (bFGF), and c-erbB-2 oncoprotein were found in SD and ED,and laminin existed at basement membrane of glandular epithelia and blood vessels.Two to three weeks after DMBA/sponge implantation, small clusters of proliferating cells were observed in necrotic oedematous area surrounding DMBA/sponge and duct-like structures and dilated ductal segments with small numbers of proliferating cells (10-25%) were found in inflammatory area surrounding necrotic oedematous … More area. These components showed positive for K8.12 keratin, S-100 alpha protein, bFGF,and c-erbB-2 oncoprotein and negative for EGF.Four to six week after DMBA/sponge implantation, keratinized epithelium extended surrounding DMBA/sponge like a cyst and some proliferating cells were observed in basal and parabasal area of cystic epithelium (* 27%). Histological and immunohistochemical features of cystic epithelium were similar to those of oral leucoplakias and c-erbB-2 oncoprotein was observed in this lesion. Squamous cell carcinomas (SCC) arose 8 to 12 weeks after DMBA/sponge implantation. Proliferating cells were observed mainly in basal and parabasal area of SCC and the frequency of proliferating cells were more than 30%. C-erbB-2 oncoprotein was observed also in the SCC.Invasive growth feature of tumor cells with breakages of basement membrane were some times found in after 12 weeks speciments.In the duct-ligated SMG,proliferating cells were increased in duct-like structures and the peak of the PCNA labeling was about 50% at the third day and then gradually decreased into 10% at the 21st day of experiment. Histological and immunohistochemical findings of duct-like structures in duct-ligated SMG were similar to those of duct-like structures which appeared during carcinogenesis. In unligated gland of experimental animals showed proliferation activity in acinar cells and its peak was at the second day (* 20%) and rapidly decrease into normal level at the 10th day of experiment.These results suggested that in case of acceleration of secretory function of SMG,secretory cells may proliferate as for the functional adaptation. However, in case of damage, ductal segments have more potential for proliferation and these cells may be the major participant cells during glandular regeneration and possibly source in the histogenesis of the majority of salivary gland tumors. Furthermore, apperance of c-erbB-2 oncoprotein in ductal segment and tumor cells, and EGF is accumulated in GCT,these findings may influences of rapidly carcinogenesis compared to another organs. Less