PDCD1 and neoplasm: We further validated our findings of the immune checkpoint gene expression and the correlation to T cells in the cohort from Kreuzinger et al. We confirmed the high gene expression levels of LAG3 and HAVCR2 in both primary and recurrent tumor tissue and a trend towards increased gene expression of TIGIT, CTLA4, and PDCD1 in recurrent tumor compared to primary tumor (Figure 6D).