Table 2. Compounds with statistical significance identified by GC-MS.

Compound	Molecular formula	RT (min)	Target ion	Qualifier ion (Q) m/z	CV for QC (%)	Change (%)	p-value	VIPb
Amino acids and derivatives
Valine	C5H11NO2	7.146	72	55	5	+ 36	0.012	1.83
Alanine	C3H7NO2	7.413	116	73	6	+ 25	0.045	1.34
Isoleucine	C6H13NO2	8.480	86	79	7	+ 21	0.035	1.15
Serine	C3H7NO3	9.682	132		8	+ 110	0.019a	2.65
Glutamic acid	C5H9NO4	14.390	246	73	8	+ 27	0.047	1.26
4-Hydroxyproline	C5H9NO3	13.306	230	73	11	+ 55	0.042a	2.18
Organic acids
Pyruvic acid	C3H4O3	6.587	174	89	6	- 22	0.014	1.35
2-Hydroxybutyric acid	C4H8O3	7.788	131	147	6	+ 31	0.029a	1.62
3-Hydroxybutyric acid	C4H8O3	8.350	147	73	9	+ 26	0.045	1.62
Sugar alcohol
Glycerol	C3H8O3	9.959	205	147	4	+ 21	0.048	1.05
Fatty acids
Myristic acid	C14H28O2	16.797	117	285	13	+ 20	0.047	1.03
Palmitoleic acid	C16H30O2	18.577	311	75	17	+ 60	0.017a	2.32
Palmitic acid	C16H32O2	18.757	313	117	8	+ 29	0.041a	1.28
Linoleic acid	C18H32O2	20.304	75	67	8	+ 41	0.032a	1.68
Oleic acid	C18H34O2	20.346	339	117	11	+ 39	0.021a	1.87
Arachidonic acid	C20H32O2	21.684	91	73	12	+ 43	0.021	1.41

^a p values corrected by Benjamin Hochberg (FDR correction),

^bVIP values with Jack-Knife confidence intervals estimative not including 0, 95% confidence level, RT: retention time; CV for QC (%): CV obtained for the same feature within the set of quality control samples.; Change: percentage of change of the abundances, calculated as (Breast cancer-control)/control, the sign indicates the direction of change in BCP group.