Abstract 1013: Location matters: unique functional and transcriptional, but not flow cytometric, characteristics of intratumoral FOXP3+ Tregs vs. Tregs from other sites of patients with lung tumors

FOXP3+ Tregs are considered important to limiting antitumor immunity but are rarely characterized clinically. We studied 227 samples from 66 lung cancer patients using blood, lymph node (LN), tumor and distant lung samples, with a mean age of 67.8±1.1 years, 67% males, 62% adenocarcinoma, 31% squamous cell carcinoma, 7% miscellaneous tumors, mean tumor size of 3.4±0.3 cm, and 21% rate of metastases. In addition to quantitating FOXP3+CD4+ Tregs, we evaluated their expression of 35 markers by flow cytometry: CD15s, CD25, CD26, CD27, CD39, CD40L, CD45RA/RO, CD62L, CD69, CD101, CD120b, CD161, CCR4, CTLA4, GARP, GITR, Helios, HLA-DR, ICOS, LAP, neuropilin, PD-1, TIGIT, Tim3, CCR4, CCR5, CCR7, CXCR3, CXCR4 and CCR8, and tested Treg suppressive function. We used PrimeFlow to evaluate mRNA expression of target genes in 100% pure human Treg cells, gated on CD4+FOXP3+ cells. FOXP3+ Tregs (%) in the CD4 cels of tumors and LN were significantly increased (p Citation Format: Wayne W. Hancock, Tatiana Akimova, Tianyi Zhang, Evgeniy Eruslanov, Sunil Singhal, Steven M. Albelda. Location matters: unique functional and transcriptional, but not flow cytometric, characteristics of intratumoral FOXP3+ Tregs vs. Tregs from other sites of patients with lung tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1013. doi:10.1158/1538-7445.AM2017-1013