Vulvo-vaginal epithelial tumors in mares: A preliminary investigation on epithelial-mesenchymal transition and tumor-immune microenvironment.

This research examines vulvo-vaginal epithelial tumors in horses, looking specifically at the process known as epithelial-to-mesenchymal transition (EMT) and the environment within these tumors. Notably, it explores the implication of equine papillomavirus, the expressions of certain proteins, and the infiltration of immune cells in benign and malignant tumors, providing fresh insights into this understudied field.

Research Focus and Methodology

• The study investigates uncommon vulvo-vaginal epithelial tumors in horses, specifically analyzing elements such as EMT and the tumor-immune microenvironment (TIME).
• The researchers primarily focused on the role of the equus caballus papillomavirus type 2 (EcPV2) infection and its link to this type of cancer.
• Various methods like histopathological, immunohistochemical, transcriptomic, hybridization, and correlation analyses are used for this research to get a holistic understanding of the condition.

Findings on EMT and Cell Expression

• The malignancy of the lesions was associated with the cytoplasmic expression of E-cadherin and β-catenin, and nuclear β-catenin expression. Membranous E-cadherin and β-catenin expression were associated with benign or potentially cancerous lesions.
• Interestingly, no distinct differences were identified between benign and malignant vulvo-vaginal lesions in horses in the expression of genes related to canonical and noncanonical wnt/β-catenin pathways.
• More malignant lesions were characterized by fewer cells showing cytoplasmic cytokeratin expression and slightly more showing cytoplasmic vimentin immunolabeling.

Understanding the Tumor-Immune Microenvironment

• The researchers found the microenvironment of malignant lesions to be associated with more CD204 M2-polarized macrophages—immune cells that play a role in immune regulation.
• This suggests that these macrophages might be enhancing the EMT process in these malignant vulvo-vaginal lesions in horses.

Implications of the Findings

• These findings underline the potential complexity involved in the progression of vulvo-vaginal epithelial tumors in horses.
• The role of the virus, EcPV2, as well as the involvement of immune cells like the CD204 M2-polarized macrophages in the progression of the disease could spur new avenues of research.
• The study also shows that while expression of certain proteins may differ between benign and malignant lesions, changes in associated gene expression may not be as clear-cut, implying a multilevel regulation of the disease.