Vascular endothelial growth factor-C expression as a biomarker of poor prognosis in esophageal squamous cell carcinoma: a meta-analysis

Visfatin upregulates VEGF-C expression and lymphangiogenesis in esophageal cancer by activating MEK1/2-ERK and NF-κB signaling

Lymph node metastasis is a recognized prognostic factor in esophageal cancer. Adipokines, including visfatin, and the molecule vascular endothelial growth factor (VEGF)-C, are implicated in lymphangiogenesis, but whether any association exists between esophageal cancer, adipokines and VEGF-C is unknown. We examined the relevance of adipokines and VEGF-C in esophageal squamous cell carcinoma (ESCC) in the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) databases. We found significantly higher levels of visfatin and VEGF-C expression in esophageal cancer tissue than in normal tissue. Immunohistochemistry (IHC) staining identified that higher levels of visfatin and VEGF-C expression were correlated with advanced stage ESCC. Visfatin treatment of ESCC cell lines upregulated VEGF-C expression and VEGF-C-dependent lymphangiogenesis in lymphatic endothelial cells. Visfatin induced increases in VEGF-C expression by activating the mitogen-activated protein kinase kinases1/2-extracellular signal-regulated kinase (MEK1/2-ERK) and Nuclear Factor Kappa B (NF-κB) signaling cascades. Transfecting ESCC cells with MEK1/2-ERK and NF-κB inhibitors (PD98059, FR180204, PDTC, and TPCK) and siRNAs inhibited visfatin-induced increases in VEGF-C expression. It appears that visfatin and VEGF-C are promising therapeutic targets in the inhibition of lymphangiogenesis in esophageal cancer.

Lymphatic vessels in cancer

The lymphatic system, composed of initial and collecting lymphatic vessels as well as lymph nodes that are present in almost every tissue of the human body, acts as an essential transport system for fluids, biomolecules and cells between peripheral tissues and the central circulation. Consequently, it is required for normal body physiology but is also involved in the pathogenesis of various diseases, most notably cancer. The important role of tumor-associated lymphatic vessels and lymphangiogenesis in the formation of lymph node metastasis has been elucidated during the last two decades, whereas the underlying mechanisms and the relation between lymphatic and peripheral organ dissemination of cancer cells are incompletely understood. Lymphatic vessels are also important for tumor-host communication, relaying molecular information from a primary or metastatic tumor to regional lymph nodes and the circulatory system. Beyond antigen transport, lymphatic endothelial cells, particularly those residing in lymph node sinuses, have recently been recognized as direct regulators of tumor immunity and immunotherapy responsiveness, presenting tumor antigens and expressing several immune-modulatory signals including PD-L1. In this review, we summarize recent discoveries in this rapidly evolving field and highlight strategies and challenges of therapeutic targeting of lymphatic vessels or specific lymphatic functions in cancer patients.

Prognostic nomogram for previously untreated patients with esophageal squamous cell carcinoma after esophagectomy followed by adjuvant chemotherapy

OBJECTIVE

The aim of the study was to establish an effective prognostic nomogram for esophageal squamous cell carcinoma after radical esophagectomy followed by adjuvant chemotherapy in those previously untreated patients.

METHODS

The clinicopathological data from 328 patients who underwent radical esophagectomy followed by adjuvant chemotherapy or not at the Tianjin Medical University Cancer Institute and Hospital between 2006 and 2010 were retrospectively studied. Nomograms which predicted survival of esophageal squamous cell carcinoma were established based on the Cox proportional hazards regression model. To determine its predictive accuracy and discriminatory capacity, the concordance index and calibration curve were calculated after bootstrapping in the internal validation. An external validation of 76 patients in 2011 was prospectively studied at the same institution. To verify the performance of the nomogram, the comparison between the nomogram and Tumor-Node-Metastasis staging system was conducted.

RESULTS

The 5-year overall survival was 43.1% in the primary cohort. Based on multivariate analyses, five independent prognostic variables including gender, tumor length, T stage, N stage and chemotherapy cycles were selected to build the nomograms to predict disease-free survival and overall survival. The concordance index of the nomogram to predict overall survival was 0.71 (95% confidence interval, 0.63-0.79), which was superior to the predictive power of Tumor-Node-Metastasis staging system (0.64) in the primary cohort. Meanwhile, the calibration curve showed good accuracy between predictive and actual overall survival. In the validation cohort, the concordance index (0.77) and calibration plot displayed favorable performances. The other nomogram to predict disease-free survival also performed well.

CONCLUSIONS

The prognostic nomogram provided individualized risk estimate of survival in patients after esophagectomy followed by adjuvant chemotherapy.

Retrograde Lymphatic Spread of Esophageal Cancer: A Case Report

The concept of the retrograde lymphatic spread of cancer cells appears to account for a subset of the essential mechanisms of cancer metastasis in various organs. However, no adequate data currently exist to illustrate the pathology of the retrograde lymphatic metastasis of cancer cells in human bodies. To shed light on this phenomenon, we report a case of a 63-year-old Japanese man who underwent an esophagectomy and lymph node dissection for early-stage esophageal cancer.The patient's clinical information was evaluated by board-certified surgeons and internists. Surgically excised materials were histopathologically evaluated by attending pathologists.Postoperative pathological examination revealed that the patient's tumor was a well-differentiated squamous cell carcinoma with negative surgical margins (T1N0M0, stage I). Apart from the primary lesion, a single lymphatic vessel invasion was found between the lamina propria and lamina muscularis of the esophagus where intralymphatic cancer cells had spread against the direction of backflow prevention valves and skipped beyond these valves without destroying them.The present case demonstrated that the retrograde lymphatic spread of cancer cells can occur in valve-equipped lymphatic vessels. Our study may not only provide a scientific basis for the concept of retrograde lymphatic metastasis but also explain a portion of the complexities associated with the lymphogenous metastasis of esophageal cancer.