This study used pan-cancer data from The Cancer Genome Atlas (TCGA) to investigate the expression patterns of members of the TXNRD and GPX gene families (TXNRD1, TXNRD2, TXNRD3, GPX1, GPX2, GPX3, and GPX4 genes) and their association with primary overall survival in 33 types of cancer, and to correlate their expression levels with the tumor microenvironment and pharmacological activity. This evidence concerns the gene TXNRD3 and cancer.