Previous studies have found that cancer cells can down-regulate the expression of G6PD via the deposition of histone H3K9 methylation (H3K9me3) on the G6PD promoter, and induce a decrease in the expression of granzyme B in cytotoxic T lymphocytes (CTLs), thereby promoting the proliferation of cancer cells [52]. The gene discussed is GZMB; the disease is cancer.