Salivary Fusobacterium nucleatum serves as a potential diagnostic biomarker for gastric cancer

Table 1 Association of Fusobacterium nucleatum levels in saliva with clinicopathologic features

Feature	Number of cases	Fusobacterium nucleatum level	P value
Age (yr)			0.780
< 61	56	153.00 (39.20-542.00)
≥ 61	64	204.00 (57.30-566.00)
Gender			0.961
Male	99	161.00 (53.52-620.60)
Female	21	213.60 (46.63-335.90)
Tumor size (cm)			0.450
< 5	76	152.90 (52.21-443.80)
≥ 5	44	239.90 (47.31-846.80)
Pathological differentiation			0.658
Well	77	147.50 (33.98-543.90)
Moderate	33	155.80 (84.94-754.60)
Poor	10	280.80 (78.46-518.70)
Invasion depth			0.227
T1	29	124.60 (32.21-415.80)
T2	60	298.30 (76.58-666.90)
T3	21	102.10 (68.62-385.70)
T4	10	223.00 (66.99-790.30)
Lymph nodes metastasis			< 0.001
N0	43	80.14 (23.98-241.80)
N1	25	324.50 (72.43-549.10)
N2	22	239.60 (79.36-501.70)
N3	30	478.00 (96.09-1054.00)

Table 2 Characteristics and levels of biomarkers among different subjects

	Normal control	Atrophic gastritis	Non-atrophic gastritis	Gastric polyps	Gastric cancer
Cases	20	31	35	26	120
Gender (male/female)	13/7	17/14	19/16	15/11	73/47
Age (yr)1	56.90 ± 16.02	62.13 ± 10.56	60.80 ± 14.54	58.17 ± 15.26	61.38 ± 10.31
CEA (mg/L)2,3	2.03 (1.22-2.56)	1.95 (1.49-53.37)	1.72 (1.44-2.60)	1.36 (1.10-1.85)	2.46 (1.38-4.63)
CA19-9 (pg/mL)2,3	6.38 (3.61-11.39)	10.67 (8.68-16.35)	10.30 (7.09-15.07)	9.20 (5.68-12.09)	11.46 (6.75-20.28)
CA72-4 (U/mL)2,3	2.86 (0.98-6.48)	0 (0-3.18)	2.41 (1.50-4.65)	1.71 (0.15-4.63)	2.58 (0-5.69)
Ferritin (ng/mL)2,3	143.15 (97.04-273.98)	96.98 (69.33-206.55)	126.70 (74.49-245.30)	182.95 (101.13-263.88)	86.20 (25.99-165.75)
Sialic acid (g/L)2,4	54.30 (51.45-56.75)	52.50 (46.50-55.30)	53.70 (48.25-60.55)	56.2 (50.53-59.65)	59.55 (53.28-65.33)
Fusobacterium nucleatum (copies/μL)2,4	16.70 (2.4-26.10)	28.611 (5.99-61.50)	12.18 (0.74-35.55)	16.32 (1.59-122.234)	177.09 (53.09-547.11)

¹Data are presented as the mean ± SD.

²Data are presented as the median (interquartile range).

³Date are compared using Kruskal-Wallis test, P < 0.05.

⁴Date are compared using Kruskal-Wallis test, P < 0.001.

CEA: Carcinoembryonic antigen; CA19-9: Carbohydrate antigen 19-9; CA72-4: Carbohydrate antigen 72-4.

Table 3 Diagnostic performance of Fusobacterium nucleatum, carcinoembryonic antigen, carbohydrate antigen 19-9, carbohydrate antigen 72-4, ferritin, and sialic acid for gastric cancer

Index	AUC	Cut-off value	Sensitivity (%)	Specificity (%)	PPV (%)	NPV (%)
Fn	0.813	67.58 copies/μL	73.33	82.14	81.48	74.19
CEA	0.620	5 ng/mL	55.00	69.64	66.00	59.09
CA19-9	0.570	69.2 pg/mL	26.67	86.61	68.09	52.43
CA72-4	0.541	6.9 U/mL	67.50	44.64	56.64	56.18
Ferritin	0.648	400 ng/mL	51.67	23.21	41.89	30.95
Sialic acid	0.693	75.4 mg/dL	60.83	70.54	68.87	62.70

AUC: Area under curve; PPV: Positive predictive value; NPV: Negative predictive value; Fn: Fusobacterium nucleatum; CEA: Carcinoembryonic antigen; CA19-9: Carbohydrate antigen 19-9; CA72-4: Carbohydrate antigen 72-4.