Analysis of CD133 positive cells in pituitary adenoma

肿瘤中的干细胞样细胞具有自我更新和多向分化的能力，在肿瘤的发生和维持中起重要作用。恶性胶质瘤中的干细胞样细胞表达CD 133。我们用常规免疫组化和生化方法检测了70例垂体腺瘤（临床无功能腺瘤和生长激素、催乳素、促肾上腺皮质激素和促甲状腺激素腺瘤）的CD 133表达。7%表达CD 133。临床无功能性腺瘤的发生率（33.3%）高于功能性腺瘤（12.0%）（p=0.085）。实时荧光定量PCR检测CD 133阳性标本中CD 133 mRNA的表达。患者年龄、性别、肿瘤大小、术后复发率与CD 133阳性率均无相关性。CD 133 ^+细胞普遍共表达CD 34、巢蛋白和VEGFR 2（KDL 1）。S-100和GFAP不与CD 133共表达。嗜铬粒蛋白A、Pit-1、SF-1和NeuroD 1均为免疫阴性，表明CD 133 ^+细胞不具有分化为功能性内分泌细胞的潜能。我们的数据表明，CD 133在垂体腺瘤中的表达与未成熟的内皮祖细胞有关，这些内皮祖细胞可能在垂体腺瘤的新生血管形成中发挥作用。CD 133 ^+细胞在垂体腺瘤新生血管形成和持续生长中的意义有待进一步研究。

Stem-like cells in tumors are capable of self-renewal and pluri-differentiation ; they are thought to play important roles in tumor initiation and maintenance. Stem-like cells in malignant glioma express CD133. We examined samples from human pituitary adenoma, a generally benign neoplasm, for CD133 expression using routine immunohistochemical and biochemical methods.Our study of 70 pituitary adenomas(clinically nonfunctioning adenomas and growth hormone-, prolactin-, adrenocorticotropic hormone-, and thyroid stimulating hormone producing adenomas) showed that 18(25. 7%) expressed CD133. This rate was higher in clinically non-functioning(33.3%) than functioning adenomas(12.0%)(p=0.085). Real-time PCR assay revealed the expression of CD133 mRNA in samples immunohistochemically positive for CD133. Neither the patient age and gender, nor the tumor size or postoperative recurrence rate correlated with CD133 positivity. CD133^+cells ubiquitously coexpressed CD34, nestin, and VEGFR2(KDL1). S-100 and GFAP were not coexpressed with CD133. Chromogranin A, Pit-1, SF-1, and NeuroD1 were immune-negative, indicating that CD133^+cells did not have the potential to differentiate into functional endocrine cells.Our data suggest that the expression of CD133 in pituitary adenomas is related to immature endothelial progenitor cells that may play a role in the neovascularization of pituitary adenomas. Further studies are needed to elucidate the significance of CD133^+ cells with respect to neovascularization and their sustainable growth in pituitary adenomas.