Departments of Pathology and Molecular Medicine, Hirosaki University Graduate School of Medicine, Hirosaki, Japan.
Pancreas. 2010 Nov;39(8):1147-54. doi: 10.1097/MPA.0b013e3181e78120.
Pancreatic endocrine tumor (PET) presents variable clinical features. Five subtypes of somatostatin receptor (SSTR) are involved in hormone secretion and cell proliferation. In this paper, we explore the correlation between the SSTR subtype messenger RNA (mRNA) expression and clinicopathological features of PET.
Twenty-one cases of PET and 5 cases of pancreatic adenocarcinomas (AC) were studied. Using total RNA extracted from paraffin sections and fresh tissues, SSTR subtype mRNA was quantified by real-time polymerase chain reaction. The hormones and MIB1 index were examined using immunohistochemical techniques.
The mRNA levels of SSTR1, SSTR2, SSTR3, and SSTR5 were high in PET compared with AC, whereas the expression of SSTR4 was low in PET and AC. Levels of each subtype did not vary with histological grades. Somatostatin receptor 2 levels in functioning tumors were slightly low compared with nonfunctioning tumors. Four distinct groups of PET were identified by hierarchical cluster analysis, and two of these groups showed reduced SSTR5 with elevation of MIB1 index.
The study showed a heterogeneous expression profile of SSTR subtype mRNA and the association of reduction in SSTR5 with high proliferative activity. Such profiling of SSTR subtypes may provide useful information on tumor biology and treatment of PET.
胰腺内分泌肿瘤（PET）表现出多种临床特征。五种生长抑素受体（SSTR）亚型参与激素分泌和细胞增殖。本文探讨了 SSTR 亚型信使 RNA（mRNA）表达与 PET 临床病理特征之间的相关性。
研究了 21 例 PET 病例和 5 例胰腺腺癌（AC）。使用从石蜡切片和新鲜组织中提取的总 RNA，通过实时聚合酶链反应定量 SSTR 亚型 mRNA。使用免疫组织化学技术检测激素和 MIB1 指数。
与 AC 相比，PET 中 SSTR1、SSTR2、SSTR3 和 SSTR5 的 mRNA 水平较高，而 SSTR4 在 PET 和 AC 中的表达较低。各亚型的水平与组织学分级无关。功能性肿瘤中 SSTR2 的水平略低于无功能性肿瘤。通过层次聚类分析，确定了 PET 的四个不同亚群，其中两个亚群表现出 SSTR5 降低和 MIB1 指数升高。
该研究显示 SSTR 亚型 mRNA 表达存在异质性，并发现 SSTR5 减少与高增殖活性相关。这种 SSTR 亚型的分析可能为 PET 的肿瘤生物学和治疗提供有用的信息。
