人视网膜母细胞瘤组织中的血管生成拟态观察及相关调控因子的作用

摘要

目的：观察人视网膜母细胞瘤（ RB）中血管生成拟态（ VM）形成情况及来源，探讨相关调控因子的作用。方法收集人RB组织的石蜡切片，采用HE染色、过碘酸-Schiff（PAS）/CD34双重染色观察RB中VM形成情况，计算血管生成拟态密度（VMD）；采用免疫组织化学方法检测ATP结合转运蛋白G超家族成员2（ABCG2）、造血干细胞抗原CD133（AC133）、CD34表达，检测缺氧诱导因子1α（HIF-1α）及其下游因子EphA2、基质金属蛋白酶（MMP）-2表达。采用Pearson相关性分析法分析VMD与上述指标的关系。结果 HE染色显示部分RB组织中除有内皮细胞衬覆的血管外，还可见肿瘤细胞围成的不规则管腔（内有红细胞）；PAS/CD34双重染色显示43份RB组织中VM阳性23例（53．48％），VMD为（26．52±8．72）个/HP，VM阳性率与RB分化程度呈负相关（r＝-0．532）、与临床分期无明显相关。 VM阳性RB组织中ABCG2阳性细胞数显著多于阴性组织中（P＜0．01），VM阳性组织中部分肿瘤细胞AC133表达阳性、VM阴性组织中未见AC133表达，所有RB组织中仅血管内皮细胞CD34阳性表达。 HIF-1α、EphA2、MMP-2在VM阳性组织中的表达均显著高于阴性组织（P均＜0．01），VMD与三者表达均呈正相关（P均＜0．01，r分别为0．694、0．630、0．795）。结论低分化RB组织中存在VM，其管壁构成可能主要来源于ABCG2阳性的肿瘤干细胞，HIF-1α及其下游因子EphA2、MMP-2表达上调可能促进VM形成。%Objective To observe the formation and origin of vasculogenic mimicry ( VM) in human retinoblastoma ( RB) and to investigate the roles of relevant regulatory factors .Methods We collected the human RB tissues to observe the formation of VM in human RB by HE staining and periodic acid-Schiff staining ( PAS)/CD34 double staining , and cal-culatee the VM density (VMD).The expression of ATP-binding cassette sub-family G member 2 (ABCG2), hemopoietic stem cell marker CD133(AC133), CD34, hypoxia inducible factor-1α(HIF-1α) and its downstream factors (EphA2 and matrix metalloproteinase 2 (MMP-2)) was detected by immunohistochemical method .The relationships among VM and the above indicators were analyzed by Pearson correlation analysis .Results HE staining showed blood vessels lined by endo-thelial cells as well as irregular lumen formed by tumor cells ( with red blood cells in it ) in some RB tissues .PAS/CD34 double staining showed 23 cases of positive VM (53.48%) in 43 RB samples, VMD was (26.52 ±8.72)/HP;the VM positive rate was negatively correlated with RB differentiation degrees (r =-0.532), and no significant correlation with the clinical stages .ABCG2 positive cells in the VM positive RB tissues were significantly more than those in the VM nega-tive RB tissues (P<0.01), a part of tumor cells expressed AC133 in the VM positive tissues, but not in the VM negative tissues, and only CD34 positive expression was observed in the vascular endothelial cells of all RB tissues .The expression of HIF-1α, EphA2 and MMP-2 in the VM positive group was significantly higher than that in the negative group ( all P<0.01), and the VMD is positively correlated with the three factors (all P<0.01; r=0.694, 0.630 and 0.795, respec-tively) .Conclusion VM exists in the poorly differentiated RB tissues , and its tube wall may mainly derive from ABCG 2 positive cancer stem cells .The up-regulated expression of HIF-1α, EphA2 and MMP-2 may promote the VM formation .