The five most frequently methylated TSGs (RASSF1, APC, CDH13, GSTP1, and CDKN2B) were the same in all groups of breast cancer (Figure 2) and, with the exception of CDKN2B, were involved in other tumors from LS patients, too, although with variable frequencies (Figure 3B). Here, GSTP1 is linked to Leigh syndrome.