Mass spectrometry-based serum peptide profiling in hepatocellular carcinoma with bone metastasis

Table 1 Patient characteristics, n (%)

Variable	With bone metastasis (n = 66)	Without bone metastasis (n = 72)
Age, yr
Range	23-84	22-78
Mean	58	59
Sex
Male	46 (70)	53 (71)
Female	20 (30)	19 (29)
Liver resection
With	55 (83)	58 (81)
Without	11 (17)	14 (19)
Set
Training set	38 (58)	38 (53)
Validation set	28 (42)	34 (47)
TNM stage of HCC
I	0	0
II	0	8
III	0	64
IV	66	0
Method for
metastasis detection1		/
MRI/CT	54
ECT/SPET-CT	66
PET-CT	12

¹Multiple methods were used to detect bone metastasis. TNM: Tumor node metastasis; HCC: Hepatocellular carcinoma; MRI: Magnetic resonance imaging; PET-CT: Positron emission tomography-computed tomography.

Table 2 Significant differential peptide peaks between bone metastasis hepatocellular carcinoma group and bone metastasis-free hepatocellular carcinoma group

Serial number	m/z	PTTA (t)	P-W test	PAD_1	PAD_2	HCC groups (n = 38)	Bone metastasis HCC groups (n = 38)
1	1780.7	3.60 × 10-4	1.58 × 10-4	0.026	0.048	110.3	333.7
2	1866.5	8.48 × 10-5	2.80 × 10-4	0.136	0.500	750.1	1703.5
3	2131.6	6.30 × 10-2	2.99 × 10-4	0.031	0.001	42.3	129.8
4	2880.4	2.00 × 10-3	3.68 × 10-4	0.100	0.005	142.5	294.9
5	1532.4	7.30 × 10-2	6.32 × 10-4	0.001	0.001	70.8	138.1
6	2901.9	9.57 × 10-4	9.38 × 10-4	0.078	0.065	99.3	182.2
7	2489.8	7.70 × 10-2	2.00 × 10-3	0.208	0.001	31.1	70.5
8	3061.1	1.02 × 10-1	2.00 × 10-3	0.010	0.001	30.1	74.9
9	2234.3	9.00 × 10-3	3.00 × 10-3	0.118	0.003	91.1	171.5
10	2864.1	7.00 × 10-3	3.00 × 10-3	0.029	0.009	135.5	337.0

Serial numbers of the top ten peaks; m/z: Mass to charge ratio; PTTA (t): P value of t-test or ANOVA (analysis of variance); P-W test: P value of the Wilcoxon test; PAD_1: P value of the Anderson-darling normal test (HCC groups); PAD_2: P value of the Anderson-darling normality test (bone metastasis HCC group); HCC group (38): Average peak of the arithmetic means of 38 HCC samples; Bone metastasis HCC group (38): Average peak of the arithmetic means of 38 bone metastasis from HCC samples. HCC: Hepatocellular carcinoma.

Table 3 Sequences of significant differential peptides

m/za	m/zb	Delta mass	Peptide sequence	Protein name	Accession number
1780.7	1779.8952	0.8048	GEYYLQNAFLVAYTK	Alpha-fetoprotein	IPI00022443
1866.5	1866.8657	-0.3657	TATSEYQTFFNPRTFG	Prothrombin	IPI00019568
2131.6	2131.9237	-0.3237	NLPSDSQDLGQHGLEEDFM	Serglycin	IPI00019372
2880.4	2880.4904	-0.0904	RPGVLSSRQLGLPGPPDVPDHAAYHPF	Isoform 2 of inter-alpha-trypsin inhibitor heavy chain H4	IPI00218192
1532.4	1532.8213	-0.4213	CSRDNTLKVIDLR	Isoform 1 of autophagy-related protein 16-2	IPI00300536
2489.8	2489.2810	0.5190	YTIAALLSPYSYSTTAVVTNPKE	Transthyretin	IPI00022432
2234.3	2235.1993	-0.8993	KREEAPSLRPAPPPISGGGYR	Fibrinogen beta chain	IPI00298497

m/z^a: Mass to charge ratio of the peptide observed in matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS); m/z^b: Mass to charge ratio of the peptide observed in LC-MS; Delta mass: The difference of the mass of peptide observed in MALDI-TOF-MS and LC-MS; Peptide sequence: The amino sequence of the peptide; Protein name: The full description of the protein that contained the peptide; Accession number: The accession number of the protein from the international protein index database.