Immune responses of six-transmembrane epithelial antigen of the prostate 4 functions as a novel biomarker in gastric cancer

Table 1 Comparison of six-transmembrane epithelial antigen of the prostate 4 levels between gastric cancer and adjacent normal tissues

	Case (n)	STEAP4		χ2	P value
		Low (%)	High (%)
Tumor	84	20 (23.81)	64 (76.19)	7.674	0.0056
Normal	84	37 (44.05)	47 (55.95)

STEAP4: Six-transmembrane epithelial antigen of the prostate 4.

Table 2 Correlation between six-transmembrane epithelial antigen of the prostate 4 expression and clinicopathological parameters in gastric cancer patients

Clinical parameters	STEAP4		P value
	Low (%)	High (%)
Age
< 60	9 (25.0)	27 (75.0)	0.5662
≥ 60	12 (20.0)	48 (80.0)
Gender
Female	6 (19.4)	25 (80.6)	0.6800
Male	15 (23.1)	50 (76.9)
T
T1-3	15 (23.8)	48 (76.2)	0.5264
T4	6 (18.2)	27 (81.8)
N
N0	7 (35.0)	13 (65.0)	0.1105
N1-N3	14 (18.4)	62 (81.8)
M
M0	21 (22.3)	73 (77.7)	0.9999
M1	0 (0)	2 (100)
Vascular invasion
No	18 (26.1)	51 (73.9)	0.1105
Yes	3 (11.1)	24 (88.9)
Clinical stage
Phase 1	2 (25.0)	6 (75.0)	0.5900
Phase 2	8 (29.6)	19 (70.4)
Phase 3	11 (18.6)	48 (81.4)
Phase 4	0 (0)	2 (100)

STEAP4: Six-transmembrane epithelial antigen of the prostate 4.

Table 3 Correlation analysis between six-transmembrane epithelial antigen of the prostate 4 and the immunomarkers in gastric cancer

Immune cells	Gene markers	STAD
		None		Tumor purity
		Cor	P value	Cor	P value
CD8+ T cells	CD8A	0.083	0.0925	0.039	0.455
	CD8B	0.039	0.427	0.012	0.823
CD4+ T cells	CD3D	0.003	0.959	-0.059	0.254
	CD3E	0.043	0.382	-0.022	0.670
	CD2	0.048	0.325	-0.006	0.914
B cells	CD19	0.152	P < 0.01	0.127	P < 0.05
	CD79A	0.185	P < 0.001	0.148	P < 0.01
Monocytes	CD86	0.153	P < 0.01	0.109	P < 0.05
	CD115 (CSF1R)	0.298	P < 0.001	0.261	P < 0.001
TAMs	CCL2	0.334	P < 0.001	0.296	P < 0.001
	CD68	0.118	P < 0.05	0.085	0.0981
	IL10	0.250	P < 0.001	0.217	P < 0.001
M1 macrophages	INOS (NOS2)	-0.113	P < 0.05	-0.142	P < 0.01
	IRF5	0.220	P < 0.001	0.201	P < 0.001
	COX2 (PTGS2)	0.325	P < 0.001	0.312	P < 0.001
M2 macrophages	CD163	0.283	P < 0.001	0.248	P < 0.001
	VSIG4	0.232	P < 0.001	0.203	P < 0.001
	MS4A4A	0.479	P < 0.001	0.194	0.0999
Neutrophils	CD66b (CEACAM8)	-0.109	0.338	-0.089	0.452
	CD11b (ITGAM)	0.407	P < 0.001	0.118	0.320
	CCR7	0.384	P < 0.001	0.118	0.319
Natural killer cells	KIR2DL1	0.087	0.0768	0.078	0.129
	KIR2DL3	0.055	0.262	0.042	0.410
	KIR2DL4	-0.065	0.184	-0.088	0.087
	KIR3DL1	0.079	0.107	0.084	0.102
	KIR3DL2	0.073	0.138	0.063	0.217
	KIR3DL3	-0.071	0.148	-0.06	0.240
	KIR2DS4	0.019	0.693	0.012	0.819
Dendritic cells	HLA-DPB1	0.129	P < 0.01	0.08	0.120
	HLA-DQB1	0.025	0.609	-0.032	0.532
	HLA-DRA	0.086	0.0789	0.046	0.376
	HLA-DPA1	0.108	P < 0.05	0.066	0.199
	BDCA-1 (CD1C)	0.370	P < 0.001	0.351	P < 0.001
	BDCA-4 (NRP1)	0.533	P < 0.001	0.504	P < 0.001
	CD11c (ITGAX)	0.258	P < 0.001	0.217	P < 0.001
Th1	T-bet (TBX21)	0.050	0.307	0.008	0.881
	STAT4	0.204	P < 0.001	0.172	P < 0.001
	STAT1	-0.051	0.304	-0.070	0.174
	IFN-γ (IFNG)	-0.195	P < 0.001	-0.229	P < 0.001
	IFN-α (TNF)	0.005	0.921	-0.045	0.387
Th2	GATA3	0.230	P < 0.001	0.205	P < 0.001
	STAT6	0.122	P < 0.01	0.119	P < 0.05
	STAT5A	0.220	P < 0.001	0.184	P < 0.001
	IL13	0.038	0.436	0.049	0.339
Tfh	BCL6	0.470	P < 0.001	0.451	P < 0.001
	IL21	-0.031	0.529	-0.055	0.285
Th17	STAT3	0.337	P < 0.001	0.310	P < 0.001
	IL17A	-0.268	P < 0.001	-0.278	P < 0.001
Treg	FOXP3	0.025	0.616	-0.028	0.589
	CCR8	0.158	P < 0.01	0.129	P < 0.05
	STAT5B	0.414	P < 0.001	0.383	P < 0.001
	TGFβ (TGFB1)	0.299	P < 0.001	0.266	P < 0.001
T cell exhaustion	PD-1 (PDCD1)	-0.060	0.221	-0.114	P < 0.05
	CTLA4	-0.072	0.141	-0.125	P < 0.05
	LAG3	-0.119	P < 0.01	-0.170	P < 0.001
	TIM-3 (HAVCR2)	0.124	P < 0.05	0.082	0.112
	GZMB	-0.121	P < 0.01	-0.169	P < 0.001

STAD: Stomach adenocarcinoma; TAM: Tumor-associated macrophage; Th: T helper cell; Tfh: Follicular helper T cell; Treg: Regulatory T cell; Cor: R value of Spearman’s correlation; None: Correlation without adjustment. Tumor purity: Correlation adjusted by tumor purity.