Tumor budding is a prognostic factor linked to epithelial mesenchymal transition in pancreatic ductal adenocarcinoma. Study report and literature review

Background

Pancreatic ductal adenocarcinoma (PDAC) has a devastatingly poor prognosis. Surgical resection is undertaken in only 20% of patients. Most of well-known prognostic factors reflect tumor stage more than its biology. So it is important to identify new biological indicators related to survival in order to develop new therapies.

Objective

To determine the relation between tumor budding and Epithelial Mesenchymal Transition (EMT) and to evaluate their impact on survival for patients after resection of PDAC.

Methods

We herein report a retrospective study of 50 patients with resected PDAC. Tumor budding, immunohistochemical expression of vimentin and other standard factors were correlated with survival using the Kaplan-Meier method and Cox multivariable survival analysis. For tumor budding assessment, an inter-observer variability study was performed using 100 images of tumor slides stained with Hematoxylin & Eosin and Pan-Cytokeratin.

Results

Tumor budding was present in all tumors. A substantial agreement between six pathologists was established in distinguishing high-grade from low-grade budding (κ = 0.6 and 0.73 for H&E and PCK images respectively). High-grade budding was identified in 56% of tumors (28/50). It was an adverse prognostic factor independent of tumor size, resection margins status, nodal status and vascular invasion (p = 0.008). Tumor budding was significantly associated with vimentin expression (p = 0.002).

Conclusions

The association of tumor budding with vimentin expression supported the idea that EMT is a key process in PDAC responsible for progression and drug resistance. Consequently, the elucidation of EMT molecular biology and development of new targeted therapy may improve disease outcome.