Detection of pancreatic cancer with normal carbohydrate antigen 19-9 using protein chip technology

Table 1 Clinical and biochemical characteristics of samples in the first part of the study n (%)

	Training set				Blind test set				P-value1
	Malignant	Benign	Healthy	P-value	Malignant	Benign	Healthy	P-value
Sex
Male	13 (56.52)	10 (55.56)	12 (60.00)	0.957	10 (45.45)	5 (50.00)	5 (33.33)	0.662	0.665
Female	10 (43.48)	8 (44.44)	8 (40.00)		12 (54.55)	5 (50.00)	10 (66.67)
Age (yr, mean ± SD)	62.61 ± 12.71	60.61 ± 8.51	55.50 ± 13.13	0.145	65.14 ± 13.02	59.10 ± 14.15	63.07 ± 12.60	0.402	0.18
Pathology
Ductal adenocarcinoma	23 (100.00)				22 (100.00)
Mucinous cystadenoma		7 (38.89)				2 (20.00)
Solid pseudopapillary tumor		4 (22.22)
Insulinoma		3 (16.67)				3 (30.00)
Serous cystadenoma		2 (11.11)				3 (30.00)
Intraductal papillary mucinous tumor		2 (11.11)				2 (20.00)
CA19-9 (U/mL, mean ± SD)	10.66 ± 8.92	11.94 ± 6.93	9.67 ± 6.94	0.382	12.45 ± 9.69	15.51 ± 11.60	10.00 ± 8.27	0.557	0.667

¹P value between the two sets. CA: Carbohydrate antigen.

Table 2 Statistics of four candidate biomarkers for screening pancreatic cancer (C) from healthy individuals (H)

	Intensity in malignant disease (n= 23)	Intensity in healthy individuals (n= 20)
m/z	(mean ± SD)	(mean ± SD)	P-value
5870.055	357.47 ± 137.81	688.97 ± 191.35	2.61E-07
6468.245	363.30 ± 265.95	1107.33 ± 356.79	3.84E-07
7777.958	2582.30 ± 1399.85	453.67 ± 726.81	5.62E-07
4291.792	669.14 ± 497.32	1562.50 ± 413.97	3.95E-06

Table 3 Predicted results of patterns in the study

	n	Training set		Blind test set
		Specificity	Sensitivity	Specificity	Sensitivity	PPV
Pattern 1	4	100%	100%	86.7%	86.4%	86.4%
Pattern 2	6	83.3%	91.3%	70.0%	77.3%	85.0%

PPV: Positive predictive value.

Table 4 Statistics of six candidate biomarkers for screening pancreatic cancer (C) from benign tumors (B)

	Intensity in malignant disease (n= 23)	Intensity in benign disease (n= 18)
m/z	(mean ± SD)	(mean ± SD)	P-value
4122.616	762.41 ± 314.68	1541.63 ± 453.43	5.17E-06
3964.253	211.84 ± 118.31	875.93 ± 547.64	3.51E-05
8920.024	1574.91 ± 686.01	540.98 ± 635.90	3.93E-05
6683.797	226.35 ± 94.75	1389.22 ± 1308.83	1.32E-04
4163.942	272.72 ± 142.38	791.27 ± 509.13	2.23E-04
4144.424	631.43 ± 392.13	2292.02 ± 1801.45	3.71E-04