Abstract 4579: A comparative immune-landscape within tumor-microenvironment: Pattern of distribution of immune cells in tumor versus tumor-adjacent normal tissues
Authors: Lin Xiaoqian , Sulaiman Read , Aske Jennifer , Mayer Paul , Rojas-Espaillat Luis , Starks David , De Pradip , Leyland-Jones Brian , Dey Nandini 
Published: August 2019

Introduction: Tumor and immune cells can determine each other’s fate. Immunotherapy targets either the PD1-PD-L1 axis which modulates immune-checkpoints or the cytotoxic CTLA4-mediated immune invasion of tumor cells. Thus the success of cellular-dynamics based immunotherapy depends on the makeup of the immune landscape within a given tumor as compared to its adjacent normal tissue. Aim: We hypothesize that as the immune-environment directly or indirectly shapes and determines the fate, drug response, and progression of an established tumor, the immune-landscape of the tumor-microenvironment will be characteristically different from that of the tumor-adjacent normal tissue. We studied the distribution pattern of selected immune cells in the tumor and tumor-adjacent normal tissues from patients with cancers of lung and ovary.

Methods: The study was approved by Avera IRB. FFPE tumor and tumor-adjacent normal tissue samples in pairs from surgically resected tissues were used for IHC to identify CD3 (Anti-CD3 [SP7] ab16669), CD4 ([EPR6855] ab133616), CD8 (ab85792), CD68 (Dako. #M0876), CD163 (Cell Signaling #93498), FOXP3 ([236A/E7] ab20034) in immune cells and PD-L1 (Clone 22C3; Dako. #M3653) in tumor cells & tumor-associated macrophages. Tonsil tissue was used for the IHC validation. Tumor and normal cells from paired specimens were compared using H&E stain & Ki-67, pS6RP, cl-caspase 3, CIP2A, and CD31 IHC-stains based on criteria of evaluation for individual protein(s). Anatomic pathological evaluation for the diagnosis of the disease was carried out by Pathologist.

Results: IHC expression of CD3, CD4, CD8, CD68, CD163, and FOXP3 in immune cells and PD-L1 in tumor cells was found heterogeneous. Although each tumor presented an individual pattern of distribution of immune cells, in most tumor samples, the identified immune cells were of tumor-cooperating phenotypes. Tumoricidal cells were rarely observed within the tumor compartment, and barely present in spaces, while tumor-friendly immune cells were frequent. In lung tumors, alveolar macrophages were predominantly of tumor-cooperating M2 types (CD68+/CD163+), whereas tumoricidal M1 macrophages (CD68+) were either absent or rare. The expression of PD-L1 in tumors did not correlate participation of any other immune cells in the tumor-microenviroment. Lung macrophages were highly positive for PD-L1 in which the intensity ranged from punctate to high.

Conclusion: We present for the first time, a tissue-based analysis of distribution pattern of different immune cells in histological subtypes of the lung and ovarian cancers, in the tumor and tumor-adjacent normal tissues. The relationship between the immune-landscape of the tumor and tumor-adjacent normal tissue is being worked out and will be presented in the meeting.

Citation Format: Xiaoqian Lin, Read Sulaiman, Jennifer Aske, Paul Mayer, Luis Rojas-Espaillat, David Starks, Pradip De, Brian Leyland-Jones, Nandini Dey. A comparative immune-landscape within tumor-microenvironment: Pattern of distribution of immune cells in tumor versus tumor-adjacent normal tissues [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4579.