To determine if the SDHD variants in thyroid cancer cells can result in damage to lipids by, e.g. lipid peroxidation, we measured the byproducts of polyunsaturated fatty acid peroxides upon decomposition, namely, malondialdehyde (MDA) and 4-hydroxyalkenals (24) in two thyroid cancer cell lines follicular thyroid carcinoma (FTC) 133-PTEN wild-type and FTC236-PTEN null cells transfected with SDHD-G12S or -H50R. This evidence concerns the gene PTEN and thyroid cancer.