SLC7A11 and melanoma: To verify overexpression of antioxidants and low pH in sarcoma and melanoma, surgical samples of human primary or metastatic sarcoma (n=10) and melanoma (n=10) were cut and immediately analyzed for the expression of xCT, thioredoxin and v-ATPase by immunohistochemistry, and for the presence of acidic pH using the pH dependent LysoSensor dye.