Correction to: SNCA correlates with immune infiltration and serves as a prognostic biomarker in lung adenocarcinoma

Correction: BMC Cancer 22, 406 (2022)

https://doi.org/10.1186/s12885-022-09289-7

Following publication of the original article [1], the authors identified an error in the order of the figures. The correct order is given below. The original article [1] has been corrected.

Figs. 1, 2, 3, 4, 5, 6, 7 and 8

Fig. 1

The expression of SNCA in different tumors was analyzed in Oncomine and TIMER databases. A Oncomine database was used to analyze the expression of SNCA gene in Pan-cancer species. Note: red represents upregulation of the target gene, while blue represents downregulation of the target gene. Threshold parameter: p-value is 0.01, fold change is 1.5. B The analysis of the expression level of SNCA in different tumors in TCGA through TIMER database. C Meta-analysis of SNCA expression was performed using five LUAD sequencing data sets through Oncomine database. D UALCAN database analysis of the mRNA expression level of SNCA in LUAD (**** P < 0.0001). E According to the analysis of UALCAN database, the protein expression level of SNCA in LUAD (**** P < 0.0001)

Fig. 2

Kaplan–Meier curve analysis of the influence of SNCA expression level in LUAD on the overall survival rate. A Kaplan–Meier curves of SNCA in all tumor patients. B–F Subgroup analysis based on age (> 65), N2, M0, stage III, and R0

Fig. 3

The correlation analysis between SNCA expression and immune infiltration, and the Kaplan–Meier survival curves of SNCA expression based on different immune cell subsets in LUAD. A The correlation between SNCA expression and the level of immune infiltration of B cells, CD8+ T cells, CD4+ T cells, macrophages, neutrophils, and dendritic cells in LUAD. B–I Correlation analysis of SNCA expression and the markers of dendritic cells, CD8+ T cells, macrophages, NK cells, regulatory T cells, neutrophils, B cells, monocytes, and neutrophils in LUAD. J–Q Relationship between SNCA expression and prognosis of LUAD in different immune cell subgroups (enriched / decreased CD4 + T cells, enriched / decreased macrophages, enriched / decreased NK cells, enriched /decreased CD8 + T cells). P < 0.05 was considered statistically significant

Fig. 4

Landscape of SNCA and immune checkpoint alteration in LUAD. Compact visualization of cases with multiple genetic alterations of SNCA and immune checkpoints is individually shown by cBioPortal, including fusion, amplification, deep deletion, truncating mutation, and missense mutation

Fig. 5

Genes related to immune regulation by SNCA in LUAD. A mRNA and protein levels of SNCA in the A549 cell line overexpressing SNCA were detected. B Volcanic map distribution of DEGs. Red dots are upregulated genes, and green dots are downregulated genes. C SNCA-regulated immune-related DEGs were obtained by Wayne analysis between the obtained DEGs and immune-related genes from Immport Resource. D Heat map showing the top 20 upregulated and top 20 downregulated immune-related DEGs. E GO analysis of immune-related DEGs, including five BP items, CC items, and MF items from top to bottom. F KEGG analysis of the top 15 immune-related DEGs (**** P < 0.0001)

Fig. 6

SNCA affects proliferation of LUAD cells in vitro via inhibiting PI3K/AKT/mTOR signaling pathway. A Proliferation of A549 cells overexpressing SNCA was assessed by CCK8; *** P < 0.001. B Effect of SNCA on A549 cell growth were evaluated by EdU assay (n = 5). Results of quantitative analysis were measured by Image J; **** P < 0.0001. C Effects of SNCA on A549 cell growth were further evaluated using a colony formation assay. Quantitative analysis of colony numbers is measured by Image J; ** P < 0.01. D Levels of PI3K, AKT, p-AKT, mTOR and p-mTOR proteins were assessed in stably-transfected A549 cells by Western blotting; ** P < 0.01, *** P < 0.001

Fig. 7

The screening of the key genes and analysis of SNCA in LUAD clinical samples. A Protein interaction network constructed by immune-related DEGs through Cytoscape. The orange node is the node with high degree, and the yellow node is the node with low degree. B The interaction network diagram of 10 node genes with the highest degree screened by Cytohubba application in Cytoscape. C–F qPCR method was used to verify the expression of four central genes in SNCA-overexpressing A549 cell line. G–J Kaplan–Meier curve was used to analyze the prognosis of four central genes in LUAD. K Statistical analysis of SNCA immunostaining score in clinical samples, ****P < 0.0001. L Immunohistochemical images of SNCA in clinical samples

Fig. 8

The analysis of SNCA promoter methylation level in LUAD. A The correlation analysis between the expression level of SNCA in LUAD samples and the methylation level of cg06632027 methylation site. B The analysis of methylation levels of four genomic fragments of SNCA promoter in tumor samples and normal samples in LUAD patient samples of the DiseaseMeth database. The expression level of SNCA methylation in LUAD patient samples downloaded from UALCAN database was analyzed with C sample type, D TNM stage, and E lymph node status. F After A549 and H1299 cells were treated with 5-aza-dC, the mRNA expression level of SNCA was detected by qPCR (* P < 0.05, ** P < 0.01, *** P < 0.001, **** P < 0.0001)