 This research will also study whether persons having particular types of genes involved in the metabolism of methionine 5-methyltetrahydrofolate-homocysteine S-methyltransferase-MTR, MTFH reductase-MTFHR, transcobalamin 2-Tc2, and apolipoprotein E APOE are more likely to have delayed adverse effects after treatment for their tumors. The findings of this study may help us understand whether this disease and its treatment may have affected some patients thinking skills, and whether this may be related to having certain genes. 