A trend toward a higher PCDC1 expression in Group 2 was observed, but by less than two-fold (average HTSeq counts of 99 in Group 1 versus 159 in Group 2; Figure 3A), which suggests that the expression level of PD-1 or PD-L1 might not provide an optimal indicator for a PD-1 positive tumor microenvironment (see below). Here, PDCD1 is linked to neoplasm.