GABRP is a Promising Prognostic Biomarker and Associated with Immune Cell Infiltration in Lung Squamous Cell Carcinoma

Figures & data

Figure 1 GABRP expression levels in human cancers. (A) Abnormal expression of GABRP in human cancers based on TCGA databases. (B) The expression of GABRP in LUSC (B and C) and LUAD (D). Abnormal expression of GABRP in lung cancer based on GSE1037 (E) and GSE43458 (F). Light blue indicates normal group, red indicates tumor group. (G) Protein levels of GABRP in normal lung tissue: https://www.proteinatlas.org/ENSG00000094755-GABRP/tissue/lung#img. Staining: low, intensity: moderate, quantity: < 25%. (H) Protein levels of GABRP in tumor tissue: https://www.proteinatlas.org/ENSG00000094755-GABRP/pathology/lung+cancer#img, Staining: medium, intensity: moderate, quantity: > 75%. *p < 0.05, **p < 0.01 and ***p < 0.001; ns indicates no significant difference.

Abbreviations: GABRP, Gamma-aminobutyric acid A receptor π subunit; TCGA, The Cancer Genome Atlas; LUSC, lung squamous cell carcinoma; LUAD, lung adenocarcinoma.

Table 1 Correlation Analysis Between GABRP Expression and Pathological Features of LUSC Patients

Characteristic	Low Expression of GABRP	High Expression of GABRP	p
n	251	251
T stage, n (%)			< 0.001
T1	45 (9%)	69 (13.7%)
T2	152 (30.3%)	142 (28.3%)
T3	47 (9.4%)	24 (4.8%)
T4	7 (1.4%)	16 (3.2%)
N stage, n (%)			0.492
N0	166 (33.5%)	154 (31%)
N1	63 (12.7%)	68 (13.7%)
N2	19 (3.8%)	21 (4.2%)
N3	1 (0.2%)	4 (0.8%)
M stage, n (%)			0.123
M0	202 (48.2%)	210 (50.1%)
M1	1 (0.2%)	6 (1.4%)
Pathologic stage, n (%)			0.328
Stage I	121 (24.3%)	124 (24.9%)
Stage II	83 (16.7%)	79 (15.9%)
Stage III	42 (8.4%)	42 (8.4%)
Stage IV	1 (0.2%)	6 (1.2%)
Primary therapy outcome, n (%)			0.549
PD	17 (4.7%)	14 (3.9%)
SD	8 (2.2%)	9 (2.5%)
PR	4 (1.1%)	1 (0.3%)
CR	151 (41.8%)	157 (43.5%)
Gender, n (%)			0.223
Female	72 (14.3%)	59 (11.8%)
Male	179 (35.7%)	192 (38.2%)
Race, n (%)			0.431
Asian	4 (1%)	5 (1.3%)
Black or African American	18 (4.6%)	12 (3.1%)
White	170 (43.7%)	180 (46.3%)
Age, n (%)			0.738
<=65	98 (19.9%)	93 (18.9%)
>65	149 (30.2%)	153 (31%)
Residual tumor, n (%)			0.410
R0	196 (47.2%)	203 (48.9%)
R1	8 (1.9%)	4 (1%)
R2	2 (0.5%)	2 (0.5%)
Anatomic neoplasm subdivision, n (%)			0.440
Left	103 (21.8%)	111 (23.5%)
Right	135 (28.5%)	124 (26.2%)
Anatomic neoplasm subdivision2, n (%)			0.897
Central Lung	67 (27.9%)	80 (33.3%)
Peripheral Lung	44 (18.3%)	49 (20.4%)
Number_pack_years_smoked, n (%)			0.304
<40	71 (16.7%)	63 (14.8%)
≥40	137 (32.2%)	154 (36.2%)
Smoker, n (%)			0.482
No	11 (2.2%)	7 (1.4%)
Yes	235 (48%)	237 (48.4%)
OS event, n (%)			0.087
Alive	153 (30.5%)	133 (26.5%)
Dead	98 (19.5%)	118 (23.5%)
DSS event, n (%)			1.000
Alive	178 (39.6%)	183 (40.7%)
Dead	44 (9.8%)	45 (10%)
PFI event, n (%)			0.378
Alive	172 (34.3%)	182 (36.3%)
Dead	79 (15.7%)	69 (13.7%)
Age, median (IQR)	68 (60, 73)	69 (63, 74)	0.107

Table 2 Univariate and Multivariate Analyses Were Used to Explore the Prognostic Value of GABRP in LUSC Patients

Characteristics	Total (N)	Univariate Analysis		Multivariate Analysis
		Hazard Ratio (95% CI)	P value	Hazard Ratio (95% CI)	P value
T stage	496
T1	114	Reference
T2	289	1.237 (0.872–1.753)	0.233	1.204 (0.824–1.759)	0.337
T3&T4	93	1.931 (1.277–2.920)	0.002	1.777 (1.117–2.828)	0.015
N stage	490
N0	317	Reference
N1	128	1.076 (0.786–1.473)	0.647
N2&N3	45	1.383 (0.887–2.158)	0.152
M stage	415
M0	408	Reference
M1	7	3.112 (1.272–7.616)	0.013	2.179 (0.879–5.403)	0.093
Gender	496
Female	130	Reference
Male	366	1.211 (0.879–1.669)	0.241
Age	490
<=65	190	Reference
>65	300	1.279 (0.960–1.704)	0.093	1.511 (1.098–2.079)	0.011
GABRP	496
Low	247	Reference
High	249	1.442 (1.097–1.895)	0.009	1.779 (1.307–2.421)	<0.001

Figure 2 High GABRP expression was associated with poor OS in LUSC patients. The Kaplan-Meier survival curves of the LUSC patients based on GEPIA (A) and TCGA (B) databases. (C) ROC curve analysis of GABRP expression in LUSC.

Abbreviations: GABRP, Gamma-aminobutyric acid A receptor π subunit; OS, overall survival; ROC, receiver operating characteristic; AUC, area under the curve.

Figure 3 Establishment of a nomogram for LUSC patients. (A) A nomogram for assessing the survival probability of 1-year, 3-year, and 5-year for LUSC. (B) Calibration curve of the prognostic risk model.

Abbreviations: GABRP, Gamma-aminobutyric acid A receptor π subunit; LUSC, lung squamous cell carcinoma.

Figure 4 Identification and functional enrichment analysis of the GABRP-related DEGs in LUSC. (A) Volcano plots of the DEGs. (B) Co-expression heatmap of top DEGs. (C) GO and KEGG enrichment analyses of GABRP-related DEGs in LUSC. ***p < 0.001.

Abbreviations: GABRP, Gamma-aminobutyric acid A receptor π subunit; DEGs, differentially expressed genes; GO, Gene Ontology; KEGG, Kyoto Encyclopedia of Genes and Genomes; CC, cellular compositions; MF, molecular functions; LUSC, lung squamous cell carcinoma.

Figure 5 The relationship between GABRP expression and stromal score, immune score, and ESTIMATE score. (A) Box diagram presented the stromal score, immune score and ESTIMATE score in the low- and high-GABRP groups. Scatter plots presented the correlation between GABRP expression and stromal score (B), immune score (C) and ESTIMATE score (D) level. **p < 0.01, ***p < 0.001.

Abbreviations: GABRP, Gamma-aminobutyric acid A receptor π subunit; ESTIMATE, Estimation of STromal and Immune cells in MAlignant Tumours using Expression.

Figure 6 The relationship between GABRP expression and immune cell infiltrations. (A) Box diagram presented the enrichment scores of 24 immune cell types in the low- and high-GABRP groups. (B) Lollipop plot presented the correlation between GABRP expression and immune cells. Scatter plots presented the correlation between GABRP expression and aDC (C), NK cells (D) and TFH (E) level. *p < 0.05, **p < 0.01, ***p < 0.001; ns indicates no significant difference.

Abbreviations: GABRP, Gamma-aminobutyric acid A receptor π subunit; ssGSEA, single-sample gene set enrichment analysis; aDC, activated dendritic cells; NK cells, natural killer cells; TFH cells, T follicular helper cells.

Figure 7 Correlation analysis of GABRP expression with immune checkpoint genes expression in LUSC. Scatter plots presented the correlation between GABRP expression and CD247 (A), CTLA4 (B), HAVCR2 (C), TIGIT (D), LAG3 (E), and PDCD1 (F) expression.

Abbreviations: GABRP, Gamma-aminobutyric acid A receptor π subunit; LUSC, lung squamous cell carcinoma.

Figure 8 Expression of GABRP in lung cancer (NCI-H1299, NCI-H1650, A549, NCI-H520, H1703, and SK-MES-1) and 16HBE cell lines. The gene expression level was measured by qRT-PCR. *p < 0.05, **p < 0.01 and ***p < 0.001.

Abbreviations: GABRP, Gamma-aminobutyric acid A receptor π subunit; qRT-PCR, quantitative reverse real-time PCR.