Correlation of NPDC1 Expression and Perineural Invasion Status with Clinicopathological Features in Patients with Colon Cancer

Abstract

Background: Colon cancer is a prevalent gastrointestinal malignancy that often exhibits distant metastasis, hindering the effectiveness of surgical interventions. In addition to well-known hematogenous and lymphatic metastasis, perineural invasion (PNI) has emerged as a significant mode of distant metastasis in colon tumors. PNI is closely associated with oncologic pain in advanced cancer patients, but the underlying mechanisms and associated biomarkers, which might be the novel therapeutic targets, remain poorly understood.

Methods: In this study, we employed large databases and bioinformatics methods to identify genes strongly linked to PNI in colon cancer and investigated their involvement in tumor nerve invasion, progression mechanisms, and chemotherapy resistance. Immunohistochemical techniques were utilized to validate the expression of target genes in 384 colon cancer tissues, and their expression was correlated with clinicopathological characteristics and patient survival data in our hospital. Furthermore, we conducted a comprehensive literature review to explore the potential functions of the target genes and their associated genes.

Results: Our screening revealed a significant correlation between neural proliferation differentiation and control-1 (NPDC1) expression and patient prognosis, suggesting a potential association with neural infiltration in colon cancer. Additionally, NPDC1 may promote tumorigenesis, progression, and chemoresistance through various related pathways.

Conclusion: Our study provides novel insights into the utility of NPDC1 as a predictive marker for PNI status, disease-free survival, and overall survival in patients with colon cancer, highlighting the prevalence of NPDC1 overexpression in patients with PNI in colon cancer.

Keywords: NPDC1; PNI; clinicopathological features; colon cancer; neural proliferation differentiation and control-1; perineural invasion.

Figure 1

Exploration of neural infiltration-associated genes in colorectal cancer. (A) Combining the Ensembl database and The Cancer Genome Atlas database to obtain the Venn diagram of colon cancer neural invasion-related genes; (B) Expression validation of four crossover genes in the GEPIA database; (C) The survival analysis forest plot of crossover genes; (D) Expression level of neural proliferation differentiation and control-1 (NPDC1) in digestive system tumors database, Genotype Tissue Expression database; (E) Forest plot: The P value, risk coefficient and confidence interval of a gene in multiple tumors are analyzed by univariate Cox regression; (F) Tumor mutational burden of NPDC1 in the digestive system.

Figure 2

Pan-cancer analysis, DNA methylation, and immune infiltration assay of neural proliferation differentiation and control-1 (NPDC1). (A) The CCLE database shows the expression of NPDC1 in various colorectal cell lines. The horizontal coordinates in the graph represent the gene expression, its vertical coordinates represent various cell lines, the size of the dots in the graph represents the high or low expression, and its various colors represent the high or low expression; (B) Expression of NPDC1 in the digestive system tumors and some head tumors from the CCLE database; (C) Kaplan-Meier plot showing survival in the high and low methylation groups dichotomized by the MethSurv platform; (D) Heatmap of DNA methylation expression levels of the NPDC1 in colon cancer by the MethSurv platform; (E) Analysis of immune infiltration of NPDC1 in the digestive system tumors; Significance of the two sample groups was tested by Wilcoxon test; (F) Heat map of the relationship between genes positively and negatively correlated with NPDC1. *P < 0.05, **P < 0.01, ***P < 0.001.

Figure 3

Significance of neural proliferation differentiation and control-1 (NPDC1) expression in colon cancer. (A) The levels of NPDC1 expression in different tissues; (B) Mulberry plots showing the correlation between NPDC1 expression levels and clinical information; (C) NPDC1 survival curves. (D) Receiver operating characteristic curve of the predictive power of the variable NPDC1 in predicting tumor and normal outcomes; (E) Expression of NPDC1 in various pathologically staged tissues; (F) Prognostic differences between patients with different pathological stages. ****P < 0.0001, ns indicates no significance.

Figure 4

Exploration of neural proliferation differentiation and control-1 (NPDC1)-associated genes and analysis of related pathways. (A) Inter-gene relationship network map with NPDC1 as the core; (B) (C) and (D) Bar chart, pie chart and functional relationship of related pathways involved in the gene set with NPDC1 as the core. *P < 0.05, **P < 0.01.

Figure 5

Prognostic value of neural proliferation differentiation and control-1 and its associated genes in patients with colon cancer. (A) Risk score curves; (B) Scatter plot distribution of survival time and survival status corresponding to different sample Riskscore; (C) Heat map of prognostic gene expression in high and low risk groups; (D) Kaplan-Meier survival curves of target genes; (E) Receiver operating characteristic curves of target gene models. The higher area values under the receiver operating characteristic curve correspond to higher predictive power.

Figure 6

Univariate and multivariate survival analysis of neural proliferation differentiation and control-1-associated genes. (A) Univariate Cox regression analysis; (B) Multivariate regression analysis; (C) Calibration curves of 1-, 3-, and 5-year survival and the calibration curves for the survival nomogram model.

Figure 7

Immunohistochemical detection of neural proliferation differentiation and control-1 (NPDC1) in colon cancer tissues. (A) Representative example of Hematoxylin and eosin (H&E) staining of perineural invasion (PNI)-negative cancer tissue; (B) Representative examples of NPDC1 immunohistochemistry in PNI-negative cancer tissues, with red arrows pointing to NPDC1 expression; (C) Representative examples of H&E staining in PNI-positive cancer tissues, with blue arrows pointing to tumor cells encircling the nerves; (D) Representative examples of NPDC1 immunohistochemistry in PNI-positive cancer tissues, with red arrows pointing to nerve tissue; (E) S-100 staining of nerve tissue infiltrating into the interior of the tumor, with red arrows pointing to nerve tissue. Scale bars = 50 μm.

Figure 8

Kaplan-Meier curves of disease-free survival (A), overall survival (B), and neural proliferation differentiation and control-1 expression levels in patients with colon cancer.

Figure 9

Validation of the significance of neural proliferation differentiation and control-1 (NPDC1) expression in other databases. (A) Proteinatlas database correlation between NPDC1 expression and patient survival. (B–D) cBioportal database clinical significance of NPDC1 expression, lymph node metastasis (B), tumor stage (C), and distant metastasis (D).