@article {Jinjnumed.121.262134, author = {Xiao Jin and Maomao Wei and Shuailiang Wang and Guochang Wang and Yumei Lai and Yunfei Shi and Yan Zhang and Zhi Yang and Xuejuan Wang}, title = {Detecting fibroblast activation proteins in lymphoma using 68Ga-FAPI PET/CT}, elocation-id = {jnumed.121.262134}, year = {2021}, doi = {10.2967/jnumed.121.262134}, publisher = {Society of Nuclear Medicine}, abstract = {Purpose: Cancer-associated fibroblasts (CAFs) that overexpress fibroblast activation protein (FAP) are enriched in many epithelial carcinomas and in hematological neoplasms. Positron emission tomography/computed tomography (PET/CT) with radiolabeled FAP inhibitor (FAPI) is a new diagnostic tool for visualizing the tumor stroma. This prospective study aimed to profile FAPs in different subtypes of lymphomas and explore the potential utility of 68Ga-FAPI PET/CT in lymphomas. Methods: In this prospective study, we recruited 73 lymphoma patients who underwent 68Ga-FAPI PET/CT and recorded and measured semiquantitative parameters and ratios of their scan results. FAPI expression was assessed by immunochemistry in samples obtained from 22 of the lymphoma patients. Results: We evaluated 11 patients with Hodgkin lymphoma (HL) and 62 with non-Hodgkin lymphoma (NHL). Significantly elevated FAP uptake was observed in HL lesions, correlating with the intensity of FAP immunostaining (score, 3+). A positive association was found between the corresponding clinical classification of NHL and the 68Ga-FAPI uptake activity of the lesion. Aggressive NHL lesions, with moderate-to-strong FAP immunostaining (score, 2+ to 3+), exhibited intense to moderate 68Ga-FAPI uptake. Indolent NHL lesions showed weak FAP staining and mild to moderate 68Ga-FAPI uptake. No statistically significant correlation emerged between the sum of the product of the diameters and the corresponding maximum standardized uptake value (P = 0.424). The tumor-to-liver ratios were 6.26 {\textpm} 4.17 in indolent NHL and \> 9 in other subtypes. Conclusion: 68Ga-FAPI imaging can be used to detect FAP expression in lymphoma lesions and may be an alternate method for characterizing lymphoma profiles.}, issn = {0161-5505}, URL = {https://jnm.snmjournals.org/content/early/2021/05/27/jnumed.121.262134}, eprint = {https://jnm.snmjournals.org/content/early/2021/05/27/jnumed.121.262134.full.pdf}, journal = {Journal of Nuclear Medicine} }