Circ_0004592: An auxiliary diagnostic biomarker for gastric cancer

Table 1 Collected tissue and plasma samples

Specimen type	Specimen origin	Specimen number
Plasma	Patients with primary GC	39 (female, 44-85 yr)
		61 (male, 42-85 yr)
	Healthy subjects	100 (40-88 yr)
	Preoperative and postoperative paired samples	21
	Patients with benign gastric lesions	15
	Patients with precancerous lesions	15
Tissue	Gastric cancer tissues	20
	Matching para-cancerous tissues	20

GC: Gastric cancer.

Table 2 The intra-assay and inter-assay repeatability of circ_0004592 and 18S rRNA

	Intra-assay	Inter-assay
	mean ± SD, CV (%)	mean ± SD, CV (%)
Circ_0004592	23.23 ± 0.48, 2.06	24.01 ± 0.91, 3.79
18S rRNA	15.32 ± 0.28, 1.83	14.87 ± 0.56, 3.77

CV: Coefficient of variation.

Table 3 The correlation between circ_0004592 expression and clinicopathological parameters of gastric cancer patients

Characteristics	No. of patients	Low expression	High expression	P value
Gender
Male	61	33	28	0.206
Female	39	17	22
Age
≤ 60	34	14	20	0.146
> 60	66	36	30
Tumor size, cm
< 5	72	36	36	0.176
≥ 5	28	14	14
Pathological differentiation
Poor-undifferentiation	59	22	37	0.002b
Well-moderate	41	28	13
Tumor depth
T1-T2	50	32	18	0.004b
T3-T4	50	18	32
Lymph node metastasis
Yes	49	19	30	0.022a
No	51	31	20
Nerve/vascular invasion
Positive	48	22	26	0.274
Negative	52	28	24
CEA
Positive	60	36	24	0.012a
Negative	40	14	26
CA199
Positive	51	25	26	0.500
Negative	49	25	24

^aP <0.05.

^bP < 0.01.

Statistical analyses were carried out using Pearson χ² test or Fisher’s exact test. were considered significant. CEA: Carcinoembryonic antigen; CA199: Cancer antigen 199; GC: Gastric cancer.

Table 4 The single or combination diagnosis of circ_0004592, carcinoembryonic antigen, and cancer antigen 199

	SEN, %	SPE, %	ACCU, %	PPV, %	NPV, %
Circ_0004592	66.00 (66/100)	84.00 (84/100)	75.00 (150/200)	80.49 (66/82)	71.19 (84/118)
CEA	60.00 (60/100)	77.00 (77/100)	68.50 (137/200)	72.29 (60/83)	65.81 (77/117)
CA199	51.00 (51/100)	84.00 (84/100)	67.50 (135/200)	76.12 (51/67)	63.16 (84/133)
Circ_0004592 + CEA	74.00 (74/100)	76.00 (76/100)	75.00 (150/200)	75.51 (74/98)	74.51 (76/102)
Circ_0004592 + CA199	67.00 (67/100)	88.00 (88/100)	77.50 (155/200)	84.81 (67/79)	72.73 (88/121)
Circ_0004592 + CEA + CA199	85.00 (85/100)	65.00 (65/100)	75.00 (150/200)	70.83 (85/120)	81.25 (65/80)

SEN: Sensitivity; SPE: Specificity; ACCU: Overall accuracy; PPV: Positive predictive value; NPV: Negative predictive value.