Nasopharyngeal carcinoma (NPC) is a malignancy arising from the epithelial lining of the nasopharynx, most commonly in the fossa of Rosenmüller (1). While relatively rare in many parts of the world, NPC exhibits a striking geographical distribution, with high incidence rates in Southeast Asia, Southern China, North Africa, and the Arctic (2). The etiology of NPC is multifactorial, involving genetic predisposition, environmental factors, and a strong association with Epstein-Barr virus (EBV) infection, which is considered a primary causative agent (3, 4).

According to the 8th edition of the American Joint Committee on Cancer (AJCC) staging system, patients with stage III and IV disease are classified as having advanced NPC. Stage III and IVA represent locally advanced disease, while stage IVB indicates metastatic disease (5). Due to the insidious onset and non-specific early symptoms, such as nasal obstruction, epistaxis, or hearing loss, approximately 70% of NPC patients present with locally advanced or metastatic disease at the time of diagnosis (6). While early-stage NPC boasts a 5-year survival rate of up to 90%, the 5-year survival rate for locally advanced NPC drops to 60-80% (7). Distant metastasis remains the primary cause of treatment failure and mortality in NPC patients (8). Therefore, identifying reliable biomarkers for early detection of metastasis and accurate prognostic assessment is crucial for optimizing treatment strategies and improving patient outcomes.

Vascular endothelial growth factor-C (VEGFC) is a key regulator of lymphangiogenesis, the formation of new lymphatic vessels. VEGFC exerts its effects by binding to its cognate receptor, vascular endothelial growth factor receptor-3 (VEGFR-3), predominantly expressed on lymphatic endothelial cells (9). The VEGFC/VEGFR-3 signaling pathway plays a critical role in tumor lymphangiogenesis, facilitating the dissemination of tumor cells to regional lymph nodes and distant sites (10). For instance, recent studies have demonstrated that enhanced VEGFC secretion promotes lymphangiogenesis and lymph node metastasis in various cancers, such as bladder cancer (11). Lymphangiogenesis, orchestrated by the VEGFC-VEGFR-3 axis and often mediated by immune cells like macrophages in the tumor microenvironment, is a pivotal step in lymphatic metastasis (12).

Insulin-like growth factor 1 (IGF1), a polypeptide hormone, is involved in regulating cell growth, proliferation, differentiation, and apoptosis. Aberrant IGF1 signaling has been implicated in the development and progression of various cancers (13). IGF1 can promote tumor cell invasion and metastasis by modulating cell adhesion and angiogenesis (14). Previous work reported a positive correlation between IGF1 concentrations and tumor size in NPC patients, suggesting its potential as a diagnostic marker (15). However, research on the combined roles of serum VEGFC, VEGFR-3, and IGF1 in relation to metastasis and prognosis specifically in the context of NPC remains relatively limited.

The rationale for selecting these three specific biomarkers is based on their distinct yet complementary roles in critical pathways of NPC progression. The VEGFC/VEGFR-3 axis is a well-established driver of lymphangiogenesis, a primary route for NPC metastasis. Concurrently, the IGF1 signaling pathway is integral to tumor cell proliferation, survival, and invasion. By investigating these markers in combination, we hypothesized that a multi-faceted biomarker panel targeting both lymphatic spread and tumor growth dynamics would provide a more comprehensive and powerful prognostic tool than markers from a single biological pathway. Given the critical roles of these molecules in tumor biology, this study aimed to retrospectively investigate the association of serum VEGFC, VEGFR-3, and IGF1 levels with metastasis and prognosis in a cohort of NPC patients. The findings could provide new insights for the prevention of NPC metastasis and offer hope for prolonging patient survival by identifying potential therapeutic targets and prognostic biomarkers.

Nasopharyngeal carcinoma, an Epstein-Barr virus-associated malignancy with a high prevalence in specific geographic regions, often presents at an advanced stage, leading to poor prognosis (1, 16). Despite advances in treatment modalities, distant metastasis remains a major challenge. This study investigated the clinical significance of serum VEGFC, VEGFR-3, and IGF1 levels as biomarkers for metastasis and prognosis in NPC patients.

Our findings revealed that elevated serum levels of VEGFC, VEGFR-3, and IGF1 were significantly associated with both the presence of metastasis and poor prognosis in NPC patients. This is consistent with the known biological roles of these molecules. VEGFC, by binding to VEGFR-3, is a potent inducer of lymphangiogenesis, creating pathways for tumor cell dissemination (17, 18). Increased VEGFC/VEGFR-3 signaling has been linked to lymphatic metastasis in various cancers, including recent reports in pancreatic (19) and breast cancer (20, 21). The higher levels of these markers in metastatic NPC patients observed in our study suggest an active lymphangiogenic process contributing to tumor spread.

IGF1 is a crucial component of the IGF signaling system, which plays a pivotal role in cell growth, survival, and metabolism (22). Dysregulation of the IGF1 pathway has been implicated in tumorigenesis and progression across multiple cancer types by promoting cell proliferation and inhibiting apoptosis (23, 24). Our data, showing elevated IGF1 in NPC patients with metastasis and poor prognosis, align with studies suggesting that IGF1 can enhance tumor invasiveness. This suggests IGF1 may create a favorable microenvironment for tumor development by inhibiting apoptosis and promoting growth, a mechanism also observed in other malignancies (25). While previous research has focused on IGF1 in cancers like gastric and ovarian cancer (23, 26), its role in NPC is becoming increasingly recognized (27).

The study also identified advanced T stage, N stage, high EBV DNA load, and elevated serum VEGFC, VEGFR-3, and IGF1 as independent risk factors for NPC metastasis. Clinical stage, particularly T and N classifications, inherently reflects tumor burden and extent of spread (28). High plasma EBV DNA load is a well-established adverse prognostic factor in NPC, reflecting tumor burden and activity (29). Our finding that high EBV DNA is an independent predictor of metastasis is consistent with contemporary literature (30). The independent predictive value of VEGFC, VEGFR-3, and IGF1, even after adjusting for these strong clinical predictors, underscores their potential as valuable molecular biomarkers. High VEGFC levels may reflect an increased capacity for distant metastasis, as suggested by studies in other cancers, which have shown that VEGFC and VEGFR-3 expression correlate with lymph node metastasis and poor outcomes (31). Similarly, a dysregulated IGF1 axis has been shown to predict unfavorable survival in NPC patients (32).

Furthermore, our ROC curve analysis and the newly developed nomogram highlight the power of a multi-marker approach. The combined biomarker panel had superior predictive accuracy for metastasis compared to individual markers. The nomogram, which integrates these biomarkers with clinical factors and EBV DNA, provides a quantitative and individualized risk assessment tool. Such models are increasingly recognized for their ability to translate complex statistical data into clinically actionable information, helping to identify high-risk patients who might benefit from more aggressive treatment or intensive surveillance (33, 34). In addition to predicting metastasis, our study demonstrates the robust prognostic value of these biomarkers for overall survival. The Kaplan-Meier analysis confirmed that high levels of each biomarker, and particularly a high-risk score from the combined classifier, were strongly associated with decreased survival time. This finding aligns with a recent meta-analysis which suggested that a multi-marker panel, incorporating indicators of angiogenesis, cell proliferation, and viral load, offered superior prognostic accuracy for survival in NPC compared to single markers (35, 36). Crucially, our subgroup analysis of metastatic patients revealed that the combined biomarker score could further stratify survival even within this advanced-stage group. This suggests that the biological profile reflected by these serum markers may indicate a more aggressive tumor phenotype, independent of the mere presence of metastases, which could have implications for selecting patients for more aggressive systemic therapies or novel targeted agents. This integrated approach aligns with the principles of precision oncology, aiming to tailor patient management based on a comprehensive risk profile.

This study has several limitations. Firstly, its retrospective design may be subject to selection bias and unmeasured confounding variables. Secondly, it was conducted at a single institution, which might limit the generalizability of the findings to other populations. Thirdly, while we identified associations, the precise molecular mechanisms linking these serum markers to NPC progression require further elucidation through functional studies. Fourthly, the study lacked a non-cancer or benign disease control group, which limits our ability to assess the specificity of these biomarkers for NPC against other conditions. Future studies should include control groups to establish more robust diagnostic and prognostic specificity. Future prospective, multicenter studies with larger sample sizes are warranted to validate these findings, including the clinical utility of the nomogram, and to explore the dynamic changes in these biomarkers during treatment and their correlation with treatment response.

In conclusion, this study demonstrates that elevated serum levels of VEGFC, VEGFR-3, and IGF1 are significantly associated with metastasis and poor prognosis in patients with nasopharyngeal carcinoma. Advanced T stage, N stage, high EBV DNA load, and high levels of these three biomarkers were identified as independent risk factors for NPC metastasis. The combined assessment of these biomarkers offers enhanced predictive value for both metastatic risk and overall survival, and the developed nomogram provides a practical tool for individualized risk stratification. These findings suggest that VEGFC, VEGFR-3, and IGF1, integrated with clinical factors and EBV status, hold promise as non-invasive tools for risk assessment in NPC, potentially guiding personalized treatment approaches.