CD274 and neoplasm: However, when immunization was combined with a conspicuous inhibition of PD-L1 expression by immunizing mice with LI tumor cells that had previously been pretreated with JQ1, the TD50 of two out of two spontaneous tumors assayed increased significantly suggesting that upon inhibition of PD-L1 the antigens of these tumors were also capable to induce a tumor-inhibitory IR.