Imaging Correlates of Differential Expression of Indoleamine 2,3-Dioxygenase in Human Brain Tumors
详细信息    查看全文
文摘
Background Tryptophan catabolism via the kynurenine pathway, mediated by indoleamine 2,3-dioxygenase (IDO), is a mechanism involved in tumor immunoresistance. Positron emission tomography (PET) with α-[11C]methyl-L-tryptophan (AMT) can quantify transport and metabolism of tryptophan in infiltrating gliomas and glioneuronal tumors. In the present study, we investigated whether increased tryptophan metabolism in brain tumors measured by PET is related to expression of IDO in resected brain tumor specimens. Methods IDO expression was assessed by immunohistochemistry in tumor specimens from 15 patients (median age, 34?years) with primary brain tumors who underwent AMT PET scanning before tumor resection. Patterns of IDO expression were compared between low- and high-grade tumors and also to AMT transport and metabolism measured on PET. Results IDO immunoreactivity was seen in tumor cells in six of seven low-grade tumors but only in one of eight high-grade tumors (p--.01); three of these latter tumors showed endothelial staining only. Low-grade neoplasms showed lower transport rate (p-lt;-.01) but higher metabolic rate (p--.003) for AMT as compared to high-grade tumors. AMT metabolic rates were lower in tumor samples with no or minimal IDO expression as compared to those with widespread IDO staining (p--.017). Conclusion Low-grade tumors show widespread IDO expression, while IDO expression in high-grade brain tumors can be absent or largely confined to endothelial cells. AMT PET can be useful to identify brain tumors with different profiles of IDO expression, thus providing a useful imaging marker for emerging treatments targeting tumor IDO activity.

© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号

地址:北京市海淀区学院路29号 邮编:100083

电话:办公室:(+86 10)66554848;文献借阅、咨询服务、科技查新:66554700