Halioseek® CR PD-L1/CD8 combines on a single slide accurate PD-L1 expression assessment by a pathologist on tumor and immune cells.
Using a proprietary high-resolution image analysis system and bioinformatics pipeline:
One mechanism by which cancer tissues limit the host immune response is via upregulation of the PD-L1/ PD-1 pathway (adaptive immune resistance). While PD-L1 expression is correlated to response to ICI’s there are strong debates about the sensitivity, specificity and standardization of PD-L1 immunohistochemistry assays (Adam et al. Ann Pathol. 2016; Scheel et al. Modern Pathology 2016).
Central to the efficacy of immune checkpoint inhibitors (ICI) is the requirement for immune cells to infiltrate into tumors. A significant correlation between the proximity of the PD-1 and PD-L1+ cells and pre-existing CD8+ T cells at the invasive tumor margin with the response to ICI treatment has been demonstrated in melanoma (Tumeh et al. Nature 2014).
In addition the combination of CD8 and PD-L1 biomarkers presence/absence have been proposed to stratify the tumor microenvironment into four different types to orient immunomodulation strategies (Taube JM, Sci Trans Med. 2012 - Sznol M, Clin Cancer Res. 2013; Teng et al. Cancer Res. 2015).