When the stability list was increased to six normalising genes, one gene (PUM1) was found to be common to both sets of samples and interestingly one gene (IPO8) in the type 1 EC group and two genes (PPIA and MRPL19) in the type 2 EC group were identical to those we identified in our previous report5 where only 3 normalising genes were used and in other cancers where 4 normalising genes were used28. This evidence concerns the gene PPIA and cancer.