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P1.03 - Poster Session with Presenters Present (ID 455)
- Event: WCLC 2016
- Type: Poster Presenters Present
- Track: Radiology/Staging/Screening
- Presentations: 1
- Coordinates: 12/05/2016, 14:30 - 15:45, Hall B (Poster Area)
P1.03-006 - Quantification of PD-L1 Expression on Tumor Cells in Non-Small Cell Lung Cancer Using Non-Enzymatic Tissue Dissociation and Flow Cytometry (ID 5095)
14:30 - 15:45 | Author(s): R. Rodriguez
Tumors use many mechanisms to evade the immune system, often manipulating pathways to evade cell death. The PD-L1/PD-1 pathway in particular, has become a promising target for immuno-oncology drug development. PD-L1/PD-1 therapy has been shown to be effective in patients with NSCLC, regardless of their PD-L1 expression profile by immunohistochemistry. This creates a challenge in determining potential responders from non-responders prior to treatment. The objective of this study was to develop a trulyquantitative technology for PD-L1 expression in NSCLC. In addition, we also present a non-enzymatic technology that creates a tumor cell suspension from fresh tumor tissue so that either FNA or fresh tissue can be used.
4 mm punches were taken from each tumor. Non-enzymatic tissue homogenization (IncellPREP; IncellDx, CA) was performed. Cells were labeled with antibodies directed against CD45 and PD-L1, fixed and permeabilized then stained with DAPI to identify intact, single cells, and to analyze cell cycle.
We compared PD-L1 expression by flow cytometry using a 1% cut-off for positivity in the tumor cell population and a 1% cut-off of cells with at least 1+ intensity in immunohistochemically stained tissue sections as positive (Table 1). As demonstrated in the table, 10 of 12 lung tumor samples were concordant while 2 were discordant, one positive by flow and negative by IHC and one negative by flow and positive by IHC. PD-L1 expression by flow cytometry varied widely (1.2% to 89.4%) even in the positive concordant cases. In addition, PD-L1 expression in the aneuploid tumor population did not necessarily agree with the expression in the diploid tumor population. Figure 1
Fine, unequivocal, quantification of PD-L1 on tumor and immune cells in NSCLC may allow for better prediction of response to therapies. The present study also offers a technology that can create a universal sample type from either FNA or fresh tissue.
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