Table 2. Summary of six reference genes and a target gene.

Gene symbol	Name	Accesion number	Assay*	Gene function
ACTB	Beta-actin	NM_001101.2	4352935E	Cytoskeletal structural protein
B2M	Beta-2-microglobulin	NM_004048.2	4333766T	Beta-chain of major histocompatibility complex class I molecules
GAPDH	Glyceraldehyde-3-phosphate dehydrogenase	NM_002046.3	4352934E	Oxidoreductase in glycolysis and gluconeogenesis
HPRT1	Hypoxanthine phosphoribosyl-transferase	NM_000194.1	4333768T	Purine synthesis in salvage pathway
TBP	TATA box binding protein	NM_003194.3	4333769T	RNA polymerase II, transcription factor
TFRC	Transferrin receptor (CD71)	NM_003234.1	4333770T	Cellular iron ion homeostasis
COL1A1	Collagen, type I, alpha 1	NM_000088.3	Hs00164004_m1	Extracellular matrix structural protein

*TaqMan probes were purchased as assays-on-demand products for gene expression (Life Technologies, USA).