Table 1.

A glance of clinical significance of OPG in cancers.

Cancer type	Analysis	Diagnostic value	Prognostic value
ESCC [82]	PEA	Increased ESCC risk with higher OPG level	Not available
HCC [78]	ELISA	Not available	Higher serum OPG associated with worse overall-survival
m-ccRCC [95]	RT-PCR	Not available	Increased RANK/OPG ratio associated with BM and worse prognosis
OSCC [83]	IHC	Not available	Elevated OPG expression associated with bone invasion, poor pathological tumor regression to neoadjuvant CRT, and worse long-term cancer-specific survival
BC and GC [64]	ELISA	Reduced of breast cancer risk and increase GC risk with higher serum OPG	Upper tertile of OPG with higher risk of cancer-related mortality particularly for GC
BC [59]	ELISA	Bone metastasis with reduce OPG level	Not available
BC [62]	ELISA	Increased risk of ER- BC with higher serum OPG	Not available
BC [63]	ELISA	Not available	Higher OPG associated with increased mortality after a BC diagnosis, particularly in ER+ patients
PCa [55]	ELISA	Bone metastases with higher OPG level	Higher serum OPG associated with worse prognosis
PCa [56]	RT-PCR	Elevated OPG mRNA expression in metastatic tumor compared to BPH	Not available
MM [72]	ELISA	Higher OPG and RANKL/OPG ratios in MM patients	Not available
PaC [81]	IHC	Upregulated OPG in PaC tissues	Upregulated OPG with poor overall survival

BC breast cancer, BPH benign prostatic hyperplasia, ELISA enzyme linked immunosorbent assay, ER estrogen receptor, ESCC esophageal squamous cell carcinoma, GC gastrointestinal cancer, HCC hepatocellular carcinoma, IHC immunohistochemistry, m-ccRCC metastatic clear-cell renal carcinoma, MM multiple myeloma, OSCC oral squamous cell carcinoma, PCa prostate cancer, PaC pancreatic cancer, PEA proximity extension assay, RT-PCR real-time polymerase chain reaction.