. 2016 Dec 19;6:13. doi: 10.1038/s41598-016-0006-3

Table 4.

Relationship between NPC circulating biomarkers and clinical stages in pre-treatment samples.

NPC circulating biomarkers	Mean Values			LR Chi-Square Values^a	Degree of Freedom	P-Values^a
NPC circulating biomarkers	Stage I	Stage II–III	Stage IV	LR Chi-Square Values^a	Degree of Freedom	P-Values^a
BamHI-W qPCR Assay (copies/mL)	98	12,140	225,847	14.15	1	0.0002^b
EBNA1-qPCR Assay (copies/mL)	13	1,146	5,658	10.84	1	0.0010^b
EBNA1-dPCR Assay (copies/mL)	10	1,699	27,885	14.52	1	0.0001^b
Canonical CTC Enumeration (cells/mL)	8	8	7	0.05	1	0.8250
Potential CTC Enumeration (cells/mL)	25	39	49	1.07	1	0.3000

Abbreviations: NPC, nasopharyngeal carcinoma; CTCs, circulating tumour cells.

^aLikelihood ratio Chi-square and P-values were determined using logistic ordinal regression for the prediction of NPC clinical stage, given the levels of NPC circulation biomarkers.

^b P-values < 0.05 were considered statistically significant.