FOXD1 is a prognostic biomarker and correlated with macrophages infiltration in head and neck squamous cell carcinoma

Abstract

Background: Forkhead Box D1 (FOXD1) is differentially expressed in various tumors. However, its role and correlation with immune cell infiltration remains uncertain in head and neck squamous cell carcinoma (HNSC).

Methods: FOXD1 expression was analyzed in The Cancer Genome Atlas (TCGA) pan-cancer data. The clinical prognosis influence of FOXD1 was evaluated by clinical survival data of TCGA. Enrichment analysis of FOXD1 was performed using R packages 'clusterProfiler'. We downloaded the immune cell infiltration score of TCGA samples from published articles, and analyzed the correlation between immune cell infiltration level and FOXD1 expression.

Results: FOXD1 was highly expressed and associated with poorer overall survival (OS, P<0.0001), disease-specific survival (DSS, P=0.00011), and progression-free interval (PFI, P<0.0001) in HNSC and some other tumors. In addition, FOXD1 expression was significantly correlated with infiltration of immune cells. Tumor-associated macrophages (TAMs) infiltration increased in tissues with high FOXD1 expression in HNSC. Immunosuppressive genes such as PD-L1, IL-10, TGFB1, and TGFBR1 were significantly positively correlated with FOXD1.

Conclusions: Our study suggests FOXD1 to be an oncogene and act as an indicator of poor prognosis in HNSC. FOXD1 might contribute to the TAM infiltration in HNSC. High FOXD1 may be associated with tumor immunosuppression status.

Keywords: FOXD1; HNSC; Pan-cancer; TAM infiltration; TCGA; immunosuppression status.

Figure 1. Pan-cancer FOXD1 expression analysis

(A), FOXD1 expression in tumor and normal tissues in pan-cancer data of TCGA. (B) Representative immunohistochemical images of FOXD1 protein expression in tissues from oral squamous cell carcinoma and oral normal epithelium. (C–J), FOXD1 expression in different stages in indicated tumor type. Data were shown as mean ± SD. *P<0.05, **P<0.01, ***P<0.001, ****P<0.0001.

Figure 2. The association between FOXD1 expression and OS of cancer patients

(A–M) Kaplan–Meier analysis of OS in 33 TCGA tumor types. Group division was based on the median of FOXD1 expression. Meaningless results were not shown.

Figure 3. The association between FOXD1 expression and DSS and PFI of cancer patients

(A–J) Kaplan–Meier analysis of DSS in 33 TCGA tumor types. group division was based on the median of FOXD1 expression. Meaningless results were not shown. (K–T) Kaplan–Meier analysis of PFI in 33 TCGA tumor types. Group division was based on the median of FOXD1 expression. Meaningless results were not shown.

Figure 4. Function and pathway enrichment analysis of FOXD1 in HNSC

(A–C) Significant GO terms of top 300 genes most positively associated with FOXD1, including BPs, MF, and CC in HNSC. (D) Significant GSEA results of FOXD1 in HNSC.

Figure 5. The difference analysis of immune cell infiltration in high- and low-FOXD1 expression groups

The immune cell infiltration level in high-FOXD1 and low-FOXD1 expression group in HNSC of TCGA cohort. Data were shown as mean ± SD. *P<0.05, ***P<0.001, ****P<0.0001.

Figure 6. The correlation analysis between immune cell infiltration and FOXD1 in HNSC

(A) The correlation between FOXD1 and relevant immune cells. Red lines represent positive correlation, green lines represent negative correlation; the deeper the color, the stronger the correlation. (B–K) Individual correlation analysis plots of FOXD1 and relevant immune cells.

Figure 7. The effects of FOXD1 on immunosuppressive status in HNSC

(A) The correlation between FOXD1 and TMB values in HNSC. Red circles represent positive correlation, cyan circles represent negative correlation, and gray circles mean no correlation. The number in the circle represents the correlation coefficient. (B) The correlation between FOXD1 and immunosuppressive genes was shown in heatmap. Red represents positive correlation, blue represents negative correlation; and the deeper the color, the stronger the correlation. Data were shown as mean ± SD. *P<0.05, **P<0.01, ***P<0.001, ****P<0.0001. (C) Correlation coefficient and −log10(P-value) of FOXD1 and CD274 are shown. Each circle represents a different tumor in TCGA. Red circle is marked for HNSC. Gray circles mean no correlation.