Table 1. Patients and primary tumour characteristics by CTC and M30-positive CTC detection at baseline.

	n	CTC negative		CTC positive		P valuea	M30+		P valueb	M30+%	P valuec
All subjects	53	22	41.5%	31	58.5%		26	84%		73
Age at diagnosis
⩽35	3	2		1		0.42	1		0.14	67
36–50	5	1		4			2			42
⩾51	45	19		26			23			78
Sex
M	41	17		24	*	1	20	*	1	70	1
F	12	5		7			6			83
T (n=30)
T1	8	3		5		0.08	5		0.29	93	0.30
T2	5	5		0			—			—
T3	16	7		9			6			55
T4	1	0		1			1			100
N (n=30)
N0	11	7		4	*	0.45	4	*	0.73	92	1
N1–N3	19	8		11			8			63
M (n=25)
M0	6	3		3		0.63	2		0.36	56	0.053
M1	7	2		5			4			63
Mx	12	6		6			6			100
Fuhrman grading (n=28)
G1	1	0		1		0.23	1		0.74	100	0.24
G2	12	8		4			3			75
G3	13	7		6			5			78
G4	2	0		2			1			34
Histology (n=44)
CC carcinoma	36	16		20	*	1	16	*	1	71	0.16
Others	8	3		5			4			53
Sites of metastasis at blood draw (n=48)
Contralateral kidney	4	4		0		0.075	—			—
Lung, mediastinal LN or liver	37	15		22			17	*	0.80	67	1
Bone	7	3		4			4			92

Distribution of CTC and M30-positive CTC in RCC patients at baseline
CTC no./7.5 ml	<1	⩾1	⩾2	⩾3	⩾4	⩾5	⩾10
No. of patients	22	31	19	14	8	5	2
Percent (%)	41.5	58.5	35.8	26.4	15.1	9.4	3.8
M30-positive no./7.5 ml	<1	⩾1	⩾2	⩾3	⩾4	⩾5	⩾10
No. of patients	5	26	16	10	6	4	1
Percent (%)	16.1	83.9	51.6	32.3	19.4	12.9	3.2

Abbreviations: CTC=circulating tumour cells; LN=lymph node; RCC=renal cell carcinoma.

^aCTC detection; χ² test or Fisher's exact(*) test were employed where appropriate.

^bM30-positive CTC detection; χ² test or Fisher's exact (*) test were employed where appropriate.

^cPercentage of M30-positive CTC; median test.