System xc−is upregulated in cancer cells and can be imaged using novel radiotracers, most commonly with (4S)-4-(3-[18F]fluoropropyl)-L-glutamic acid (18F-FSPG). The aim of this review was to summarise the use of18F-FSPG in humans, explore the benefits and limitations of18F-FSPG, and assess the potential for further use of18F-FSPG in cancer patients. To date, ten papers have described the use of18F-FSPG in human cancers. These studies involved small numbers of patients (range 1–26) and assessed the use of18F-FSPG as a general oncological diagnostic agent across different cancer types. These clinical trials were contrasting in their findings, limiting the scope of18F-FSPG PET/CT as a purely diagnostic agent, primarily due to heterogeneity of18F-FSPG retention both between cancer types and patients. Despite these limitations, a potential further application for18F-FSPG is in the assessment of early treatment response and prediction of treatment resistance. Animal models of cancer have shown that changes in18F-FSPG retention following effective therapy precede glycolytic changes, as indicated by18F-FDG, and changes in tumour volume, as measured by CT. If these results could be replicated in human clinical trials, imaging with18F-FSPG PET/CT would offer an exciting route towards addressing the currently unmet clinical needs of treatment resistance prediction and early imaging assessment of therapy response.
系统xc−在癌细胞中表达上调，可通过新型放射性示踪剂进行成像，其中最常用的是(4S)-4-(3-[18F]氟丙基)-L-谷氨酸（18F-FSPG）。本综述旨在总结18F-FSPG在人体中的应用，探讨其优势与局限，并评估其在癌症患者中的进一步应用潜力。截至目前，已有十篇论文报道了18F-FSPG在人类癌症中的应用。这些研究涉及少量患者（1-26例不等），评估了18F-FSPG作为广谱肿瘤诊断剂在不同癌症类型中的应用价值。各临床试验结果存在差异，这限制了18F-FSPG PET/CT作为单纯诊断剂的应用范围，主要原因是18F-FSPG在不同癌症类型和患者间的滞留存在异质性。尽管存在这些局限，18F-FSPG在早期治疗反应评估和治疗耐药性预测方面具有潜在应用前景。癌症动物模型显示，有效治疗后18F-FSPG滞留的变化先于糖代谢变化（通过18F-FDG显示）和肿瘤体积变化（通过CT测量）。若这些结果能在人类临床试验中得到复现，18F-FSPG PET/CT成像将为解决当前治疗耐药性预测和早期治疗反应影像评估的临床需求提供新途径。
Is System xc−a Suitable Target for Tumour Detection and Response Assessment with Imaging?
肿瘤(癌症)患者之家