GPX2 and cancer: While variability among liver samples within normal and within malignant tissues (e.g., GPX2, GSR, GSS, and GSTP1) and among lung samples within normal and within malignant tissues (GSS, GLRX (Figure 2) and G6PD (Figure 3) below) may be attributed to the low number of sample sizes, we raise the possibility that each of the tumors may also be in slightly different transition stages in developing their dependency on specific enzymes to support the cancer.