87P - Identification of subsets of tumor infiltrating lymphocytes in primary brain tumors using multi-color panel flow cytometry (87P)

Date 08 December 2017
Event ESMO Immuno-Oncology Congress 2017
Session Lunch & Poster Display session
Topics Cancer Immunology and Immunotherapy
Head and Neck Cancers
Presenter Idan Ben-Horin
Citation Annals of Oncology (2017) 28 (suppl_11): xi6-xi29. 10.1093/annonc/mdx711
Authors I. Ben-Horin1, A. Shenkar2, T. Alter-Regev2, G. Diamant2, N. Shapira2, Z. Ram3, I. Volovitz2
  • 1Oncology, Tel-Aviv Sourasky Medical Center, 64239 - Tel Aviv/IL
  • 2Cancer Immunotherapy Lab, Tel-Aviv Sourasky Medical Center, Tel Aviv/IL
  • 3Neuro-surgery, Tel-Aviv Sourasky Medical Center, Tel Aviv/IL

Abstract

Background

Prognosis of primary brain tumors is poor with a 5-year overall survival (OS) raging between 10 to 27%. The prognostic significance of T-cells in these tumors has been a matter of debate with conflicting evidence. Data on other immune cell populations is scarce and at times methodologically questionable. The goal of this work was to characterize the different immune cell populations in primary brain tumors and in patients’ peripheral blood and to investigate its prognostic value.

Methods

Brain tumors and blood samples were collected from 35 patients with primary brain tumors (23 glioblastoma multiforme (GBM), 5 grade 3 (G3) gliomas and 7 grade 2 (G2) gliomas). PBMC's and dissociated tumor samples were stained with an 8 color panel. Samples were assayed by flow cytometry and analyzed using the FlowJo Tristar software. OS and progression free survival (PFS) data were collected from patients’ files. ripheral blood and to investigate its prognostic value.

Results

Statistically significant differences between tumor infiltrating lymphocytes (TILs) were demonstrated with GBM tumors having a 15-fold higher level of T-helper (Th) cells than G2 and G3 gliomas. Cytotoxic T-cells (CTL) levels’ in GBM were 8-fold higher than in G2 gliomas. ɣα T-cells occurred in all gliomas in similar frequencies. Natural killer (NK) cells were rare, representing approximately one cell per million in gliomas. There was a positive correlation between Th levels and CTL levels in G2 gliomas (R = 0.8), G3 gliomas (R = 0.8) and in GBM (R = 0.89). NK cells did not correlate with any other lymphocytic subset. Positive correlations were also identified between Th levels in the tumor and the peripheral blood in GBM tumors (R = 0.67). A weaker correlation (R = 0.84) between NK cells in G3 gliomas and the peripheral blood was also identified. No correlation between OS or PFS and TILs levels was demonstrated. Similarly, no correlation between age and TIL levels was found, though age was negatively correlated with OS and PFS.

Conclusions

The data suggests to a correlation between tumor grade and T-cells infiltration in gliomas with only a partial correlation between infiltration in the primary tumor and the peripheral blood. TILs were not found to have a prognostic value.

Clinical trial identification

Legal entity responsible for the study

Cancer immunotherapy lab, Tel-Aviv Sourasky Medical Center

Funding

None

Disclosure

All authors have declared no conflicts of interest.