By estimating the cytotoxic T lymphocyte (CTL) activities through Perforin (encoded by PRF1) and Granzyme B (encoded by GZMB) expression, we observed a negative correlation between RGMB expression levels and CTL activities in 30 of 33 cancer types (p = 2.6 × 10−6, χ2 test, Fig. 5A). Here, PRF1 is linked to cancer.