Table 1. Exact P values of group differences between benzene-exposed and unexposed subjects for selected differentially expressed proteins in the discovery, validation, and combined data sets.

		Discovery set*		Validation set*
m/z	Conditions fraction/surface	All samples (n = 20)	Excluding hemolyzed samples (n = 17)	All samples (n = 20)	Excluding hemolyzed samples (n = 17)	Combined set† (n = 34)
Up-regulated
43,359	F6-WCX2	0.0068	0.043	0.052	0.16	0.76
44,476	F1-WCX2	0.0089	0.070	0.35	0.96	0.32
44,733	F6-WCX2	0.0021	0.0097	0.63	0.54	0.12
Down-regulated
4,057‡	F6-WCX2	1.3 E-4	0.0012	0.14	0.014	2.3 E-05
6,632	F4-IMAC3	0.0021	0.019	0.17	0.744	0.32
6,435	F4-IMAC3/H50§	4.9 E-4	0.0046	0.48	0.96	0.12
6,838	F6-WCX2	0.0068	0.055	0.32	0.89	0.47
7,763	F4/F6-IMAC3/WCX2¶	4.3 E-5	4.1 E-4	0.029	0.0031	1.8 E-06
8,206	F6-WCX2	0.0011	0.0097	0.85	0.27	0.011
8,225	F6-H50	0.0029	0.019	0.68	0.54	0.026
8,690	F4-IMAC3	0.0068	0.043	0.25	0.96	0.092
8,765	F6-WCX2	0.0052	0.033	0.74	0.42	0.053
9,287	F6-IMAC3/WCX2∥	4.3 E-5	4.1 E-4	0.019	0.0031	3.8 E-06
1,2581	F4-H50	0.0015	0.014	0.25	0.54	0.034
1,7310	F4-IMAC3	0.0039	0.033	0.32	0.47	0.26
2,2229	F4-WCX2	0.0052	0.043	0.74	0.47	0.11
2,6059	F4-H50	0.0015	0.014	0.97	0.42	0.092
7,3128	F6-WCX2	0.0089	0.070	0.85	0.23	0.020

^*P values were calculated based on the average intensities of the identified peak (Wilcoxon exact test)

^†P values were calculated based on the RAI (RAI = average intensity/mean of average peak intensity in control population) of the identified peak (Wilcoxon exact test)

^‡Proteins in boldface type were significantly differentially expressed in the same direction between exposed and unexposed subjects in both the discovery and validation sets

^§Data presented based on F4-IMAC3; results of F4-H50 were essentially similar

^¶Data presented based on F4-IMAC3; results of the F6-WCX2 were essentially similar

^∥Data presented based on F6-WCX2; results of the F6-IMAC3 were essentially similar