GPX3 and chronic myelogenous leukemia, BCR-ABL1 positive: However, recent studies reveal a paradoxical role for GPX3 in malignancies: promoter hypermethylation silences GPX3 expression in hepatocellular carcinoma, lung cancer, and chronic myeloid leukemia, facilitating tumor progression (An et al., 2016; Yao et al., 2015b).