Follicular lymphoma signature. Heat map showing the gene expression profile data of 33 FL cases normalized with follicular hyperplasia cases. Red indicates high level of expression in tumors versus normal cells; blue indicates low-level expression. Genes were ranked according to mean intensity of expression. With the exception of histone subunits, GCET1 (Serpina9) expression was, in absolute numbers, the strongest of all the genes included in the FL signature. Note the stronger expression of GCET1 compared with other well-established GC markers, such as MME (CD10) and BCL6 (not shown in the figure), and novel GC markers, such as KLHL 6 and DTX1.