TIGIT and neoplasm: To further elucidate the effect of inhibiting PD-1 and TIGIT tumour cell intrinsic signalling on pro-survival pathways in OAC cells, the levels of anti-apoptotic proteins Bcl-2 and Bcl-xL were assessed following single agent PD-1 and TIGIT blockade in OE33 and OE19 cells (Fig. 5.