Interestingly, while the anti-PD1 antibody did not slow tumor progression in the PyMT model, despite the high level of PD-1 expression on tumor-infiltrating T cells, the anti BTLA antibody markedly decreased tumor growth, when looking at the overall tumor burden (Figure 2B), the primary tumor (Figure 2C) or average tumor size (Figure 2D). Here, PDCD1 is linked to neoplasm.