Author(s): Anna Sophie Berghoff, Gerda Ricken, Dorothee Wilhelm, Orsolya Rajky, Georg Widhalm, Karin Dieckmann, Peter Birner, Rupert Bartsch, Christoph Zielinski, Matthias Preusser; University of Vienna, Vienna, Austria; Institute of Neurology, Medical University of Vienna, Vienna, Austria; Medical University of Vienna, Vienna, Austria; Department of Medicine I and Comprehensive Cancer Center CNS Tumours Unit, Medical University of Vienna, Austria, Vienna, Austria; Medical University Vienna, Vienna, Austria; Department for Radiation Therapy and Radiation Biology, Medical University of Vienna, Vienna, Austria; Institute of Clinical Pathology and Comprehensive Cancer Center CNS Tumours Unit, Medical University of Vienna, Vienna, Austria; Department of Medicine I, Clinical Division of Oncology and Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria
Abstract Disclosures
Abstract: Background: Novel insights in the pathobiology of SCLC BM are needed for development of new treatment strategies. Methods: TIL subsets (CD3+, CD8+, CD45RO+, FOXP3+ and PD-1+) and expression of PD-L1 was studied in a series of 32 SCLC BM specimens and 4 matched primary tumor specimens using immunohistochemistry. Results: TIL infiltration was present in 30/32 (93.8%) BM specimens. CD3+ TILs were observed in 30/32 (93.8%) BM specimens, CD8+ TILs in 25/32 (78.1%), CD45RO+ TILs in 15/32 (46.9%), FOXP3+ TILs in 15/32 (46.9%) and PD-1+ TILs in 1/32 (3.1%) BM specimens. Dense infiltration with CD45RO+ TILs was associated with a significantly longer median survival time (11 months; 95% CI 0.000- 26.148) as compared to absence of CD45RO+ TILs (5 months; 95% CI 0.966- 9.034; p = 0.007; log rank test). Membranous PD-L1 on tumor cells was observed in 24/32 (75.0%) BM specimens, 11/32 (34.4%) cases presented with membranous PD-L1 expression in over 5% of viable BM tumor cells. PD-L1 expression on tumor infiltrating macrophages was observed in 9/32 (28.1%) specimens and on TILs in 8/32 (25.0%). Among matched primary tumors, all (4/4; 100%) specimens showed TIL infiltration, while PD-L1 expression found in only 1/4 (25.0%) specimen. Conclusions: TIL infiltration and PD-L1 expression are frequently observed in SCLC BM. Presence of CD45RO+ memory T-cells in SCLC BM seems to be associate with favorable survival times. Therefor, our data shows that SCLC BM have an immune active microenvironment that may be targetable by immune-modulating drugs.
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