Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
Histopathology. 2012 Nov;61(5):801-9. doi: 10.1111/j.1365-2559.2012.04300.x. Epub 2012 Jul 17.
Gastrointestinal stromal tumours (GISTs) typically harbour KIT or PDGFRA mutations; 15% of adult GISTs and >90% in children lack such mutations ('wild-type' GISTs). Paediatric and occasional adult GISTs show similar, distinctive features: multinodular architecture and epithelioid morphology, indolent behaviour with metastases, and imatinib resistance. Recent studies have suggested that these tumours can be identified by loss of succinate dehydrogenase subunit B (SDHB) expression. The aim of this study was to validate the predictive value of SDHB immunohistochemistry in a large genotyped cohort.
SDHB expression was examined in GISTs with known genotypes: 179 with KIT mutations, 32 with PDGFRA mutations, and 53 wild type. Histological features were recorded without knowledge of genotype or SDHB status. SDHB was deficient in 22 (42%) wild-type GISTs. All other tumours showed intact SDHB expression. All SDHB-deficient GISTs with known primary sites arose in the stomach, and had multinodular architecture and epithelioid or mixed morphology. None of the wild-type GISTs with intact SDHB showed multinodular architecture, and only four (13%) had epithelioid morphology.
SDHB-deficient GISTs are wild-type gastric tumours with distinctive histology. Immunohistochemistry for SDHB can be used to confirm the diagnosis of this tumour class. SDHB expression is retained in all GISTs with KIT and PDGFRA mutations.
胃肠道间质瘤（GIST）通常存在 KIT 或 PDGFRA 突变；15%的成人 GIST 和>90%的儿童 GIST 缺乏这些突变（“野生型”GIST）。儿童和偶尔的成人 GIST 表现出相似但具有特征性的特征：多结节结构和上皮样形态、转移后的惰性行为和伊马替尼耐药性。最近的研究表明，这些肿瘤可以通过琥珀酸脱氢酶亚基 B（SDHB）表达缺失来识别。本研究旨在验证 SDHB 免疫组化在大型基因分型队列中的预测价值。
在已知基因型的 GIST 中检查 SDHB 表达：179 例存在 KIT 突变，32 例存在 PDGFRA 突变，53 例为野生型。记录组织学特征，而不了解基因型或 SDHB 状态。22 例（42%）野生型 GIST 存在 SDHB 缺失。所有其他肿瘤均显示完整的 SDHB 表达。所有已知原发部位为胃的 SDHB 缺失的 GIST 均具有多结节结构和上皮样或混合形态。没有一个具有完整 SDHB 的野生型 GIST 具有多结节结构，只有 4 例（13%）具有上皮样形态。
SDHB 缺失的 GIST 是具有独特组织学特征的野生型胃肿瘤。SDHB 的免疫组化可用于确认该肿瘤类别的诊断。SDHB 表达在所有存在 KIT 和 PDGFRA 突变的 GIST 中均保留。
