Table 2.

List of potential reference genes.

Gene symbol	Gene name	Ensembl gene ID	Function	CV	Rank	No. of articles
SNW1	SNW domain-containing 1	ENSG00000100603	Signal transduction, regulation of transcription and splicing	0.189	1	0
CNOT4	CCR4-NOT transcription complex subunit 4	ENSG00000080802	Global transcriptional regulation, deadenylase, signal transduction, E3 ubiquitin ligase	0.205	3	0
PUM1	Pumilio RNA binding family member 1	ENSG00000134644	Regulation of the stability and function of specific mRNAs	0.235	8	11
PCBP1	Poly(rC) binding protein 1	ENSG00000169564	mRNA stabilization, alternative splicing, regulation of transcription and translation	0.291	161	2
IPO8	Importin 8	ENSG00000133704	Protein transport—nuclear import of proteins with a classical nuclear localization signal	0.336	637	13
HNRNPL	Heterogeneous nuclear ribonucleoprotein L	ENSG00000104824	mRNA splicing, stabilization, regulation of transcription and translation	0.347	791	1
TBP	TATA-box binding protein	ENSG00000112592	Transcription—general transcription factor	0.347	813	70
UBC	Ubiquitin C	ENSG00000150991	Protein catabolism—ubiquitylation of damaged/unfolded proteins	0.366	1150	29
PPIA	Peptidylprolyl isomerase A	ENSG00000196262	Protein folding—Cis–trans isomerization of proline imidic peptide bonds	0.402	1893	49
RPL30	Ribosomal protein L30	ENSG00000156482	Translation—component of the 60S ribosomal subunit	0.420	2294	4
RPL13A	Ribosomal protein L13a	ENSG00000142541	Translation—component of the 60S ribosomal subunit	0.438	2715	35
YWHAZ	Tyrosine 3-monooxygenase/ tryptophan 5-monooxygenase activation protein zeta	ENSG00000164924	Signal transduction—central hub protein for many signal transduction pathways	0.462	3258	37
ACTB	Actin beta	ENSG00000075624	Cytoskeletal structural protein	0.472	3484	113
GAPDH	Glyceraldehyde-3-phosphate dehydrogenase	ENSG00000111640	Metabolism—oxidoreductase in glycolysis and gluconeogenesis	0.492	3909	165
PGK1	Phosphoglycerate kinase 1	ENSG00000102144	Metabolism—kinase in glycolysis and gluconeogenesis	0.497	4014	29
HMBS	Hydroxymethylbilane synthase	ENSG00000256269	Metabolism—heme biosynthesis	0.551	4966	22
HPRT1	Hypoxanthine phosphoribosyltransferase 1	ENSG00000165704	Metabolism—purine synthesis in salvage pathway	0.551	4973	65
EEF1A1	Eukaryotic translation elongation factor 1 alpha 1	ENSG00000156508	Translation—aminoacyl-trna delivery to the ribosome	0.557	5060	12
ALAS1	5'-aminolevulinate synthase 1	ENSG00000023330	Metabolism—heme biosynthesis	0.578	5397	10
SDHA	Succinate dehydrogenase complex flavoprotein subunit A	ENSG00000073578	Metabolism—part of the mitochondrial respiratory chain	0.590	5579	35
GUSB	Glucuronidase beta	ENSG00000169919	Metabolism—degradation of dermatan and keratan sulfates	0.713	7074	24
TFRC	Transferrin receptor	ENSG00000072274	Metabolism—cellular iron uptake	0.738	7316	10
B2M	Beta-2-microglobulin	ENSG00000166710	Immunity—β-chain of major Histocompatibility complex class I molecules	0.906	8802	78
POLR2A	RNA polymerase II subunit A	ENSG00000181222	Transcription—RNA polymerase	1.143	10,376	12

Coefficient of variation (CV) and the corresponding rank is calculated from the relative expression data in the RNA HPA cell line gene dataset from The Human Protein Atlas^39,40. Genes are arranged in ascending order of the rank. The genes used in the present study are shown in bold. Genes suggested by Jo et al. are shown in italic³⁴. For details regarding the No. of articles, refer to “Methods”.