Low values of 5-hydroxymethylcytosine (5hmC), the "sixth base," are associated with anaplasia in human brain tumors. - Kraus TF; Globisch D; Wagner M; Eigenbrod S; Widmann D; Münzel M; Müller M; Pfaffeneder T; Hackner B; Feiden W; Schüller U; Carell T; et al. (International journal of cancer, 2012)