PD-L1 is not constitutively expressed on Tasmanian devil facial tumor cells but is strongly upregulated in response to IFN-γ and can be expressed in the tumor microenvironment oleh Andrew Steven Flies, Andrew Steven Flies, Alan Bruce Lyons, Lynn M Corcoran, Anthony T Papenfuss, Anthony T Papenfuss, Anthony T Papenfuss, James M Murphy, Graeme W Knowles, Greg M Woods, Greg M Woods, John Dominic Hayball, John Dominic Hayball