Expression and prognostic value of EGF-like domain multiple 6 in uterine corpus endometrial carcinoma and its correlation with immune cell infiltration

Abstract

Uterine corpus endometrial carcinoma (UCEC) is a common malignancy that affects the female reproductive tract, and it is characterized by high rates of both morbidity and mortality. This study investigated epidermal growth factor-like domain multiple 6 (EGFL6) as a potential diagnostic and prognostic biomarker in patients with UCEC. RNA sequencing data and clinical information from patients with UCEC were obtained from The Cancer Genome Atlas. Logistic regression analysis was used to assess the correlations between EGFL6 expression and clinical features. Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and Gene Set Enrichment Analysis were performed to evaluate the EGFL6-related biological characteristics and signaling pathways. Immunohistochemistry was performed using UCEC tissue microarrays to assess EGFL6 expression. The Kaplan-Meier method and Cox regression analyses were used to evaluate the prognostic significance of EGFL6. Three nomograms were developed to predict overall survival, disease-specific survival, and progression-free interval probabilities at 1, 3, and 5 years after diagnosis. The expression of EGFL6 was validated using quantitative real-time PCR. Our findings demonstrate that EGFL6 is markedly overexpressed in UCEC and is associated with unfavorable clinical characteristics, including clinical stage and histological type. Gene Ontology, Kyoto Encyclopedia of Genes and Genome and Gene Set Enrichment Analysis highlighted its possible association with various key signaling pathways. Additionally, EGFL6 expression was associated with decreased immune cell infiltration, particularly regulatory T cells (Tregs) (r = - 0.219, p < 0.001) and CD8 + T cells (r = - 0.217, p < 0.001). Overall, EGFL6 expression was associated with a poor patient prognosis in patients. In conclusion, EGFL6 is a potential biomarker for UCEC, and could greatly improve of diagnostic and prognostic evaluation.

Keywords: Biomarker; EGF-Like domain multiple 6; Immune infiltration; Prognosis; Uterine Corpus endometrial carcinoma.

Fig. 1

EGFL6 expression levels in UCEC. A Analysis of EGFL6 expression using the TCGA-UCEC dataset (Wilcoxon rank-sum test, p < 0.001). B EGFL6 expression in paired UCEC samples (t-test, n = 23). C ROC curve of EGFL6 in UCEC. D EGFL6 expression in adjacent noncancerous tissues (scale bar: 100 μm). E EGFL6 expression in UCEC tissues (scale bar: 100 μm). F Statistical analysis of IHC results (t-test, n = 20). (*P < 0.05, **P < 0.01, ***P < 0.001).

Fig. 2

EGFL6 expression is significantly correlated with various clinical features in UCEC. A Age. B Clinical stage. C Weight. D Histological type. E Histologic grade. F Menopause status. (Wilcoxon rank-sum test, error bars as SD), (*P < 0.05, **P < 0.01, ***P < 0.001).

Fig. 3

Analysis of DEGs associated with EGFL6 in UCEC. A Volcano plot illustrating EGFL6-related DEGs in UCEC. B Top 10 EGFL6-related DEGs in UCEC. C GO and KEGG analysis of the DEGs. D GSEA of DEGs in UCEC. (*P < 0.05, **P < 0.01, ***P < 0.001).

Fig. 4

Methylation profile of EGFL6 in UCEC. A Heatmap depicting the methylation levels of EGFL6 in UCEC. Relations between specific methylation sites and patient outcomes are shown for: B cg07810164, C cg00932276, D cg12817924, E cg26310256, F cg23083672, and G cg12461113.

Fig. 5

Relation between EGFL6 expression and immune cell infiltration. A Overall correlation between EGFL6 expression and various immune cell populations. B Correlation with Tregs. C Correlation with CD8 + T cells. D Correlation with resting dendritic cells. E Association with Tregs. F Association with CD8 + T cells. G Association with resting dendritic cells. (*P < 0.05, **P < 0.01, ***P < 0.001).

Fig. 6

Increased EGFL6 expression levels are associated with decreased survival rates in UCEC. A OS. B DSS. C PFI.

Fig. 7

Nomograms and calibration curves illustrating OS, DSS, and PFI predictions in UCEC. A Nomogram for OS in UCEC. B Calibration curve for OS. C Nomogram for DSS. D Calibration curve for DSS. E Nomogram for PFI in. F Calibration curve for PFI in UCEC. G ROC curves for the OS nomogram. H ROC curves for the DSS nomogram. I ROC curves for the PFI nomogram.

Fig. 8

EGFL6 expression is closely correlated with various clinical subgroups of UCEC. A Age. B Histologic grade: G2/G3. C BMI. D Therapy outcome: PR or CR. E Tumor invasion: ≤50%. F Receipt of radiation therapy. G Diabetes status. H Hormone therapy: No. I Menopause status: postmenopausal.