HK criterion and the resulting number of HK genes in the GSE2361 set using different methods.

aAny gene is an HK gene if it has an expression intensity (x) > = 200, as recommended by [2], in at least 35 tissues. N is the number of tissues.
bThe p value for gene expression intensity needs to be less than 0.01 to make a detection call of ‘Present’ [13], and a gene needs to have a ‘Present’ call in at least 35 tissues to be considered an HK gene. N is the number of tissues.
cFollowing [15], genes with an FPEI score above 100 in at least 35 tissues were defined as HK genes. N is the number of tissues.
dTSI[16] is bounded between 0 and 1. A lower TSI indicates a lower tendency for the gene to be TS (or a higher tendency for it to be HK). The 0.1 threshold was chosen following [16].
eFor each gene, the Näive Bayes classifier [18] calculates a probability (P) of it being an HK gene; in this study, we choose those with a P value greater than 0.8 to be classified as HK genes.
fAccording to [6], those genes with an RPKM (reads per kilobase of exon model per million mapped reads) score greater than 0.3 were classified as HK genes.