melanoma tumors in horses: a review of cases series, known knowledge, and upcoming efforts

This review paper aims to provide not only a comprehensive view of the occurrence of melanoma tumors in equines, the pathobiology of the disease, diagnosis, and treatment processes, but also to provide a review of several cases that have been visited by the authors. equine melanocytic tumors are among horses most prevalent skin cancers, with a notable preference for gray horses. despite their typically slow growth rate, which often leads to the misconception that they are benign, these tumors can indeed be malignant. the tumors’ development is closely linked to genetic mutations in specific genes such as stx17, asip, and mitf. additionally, there is an association between the graying process in horses and the development of these melanocytic tumors. there are several types of melanocytic tumors identified in horses: naevus, dermal melanoma, dermal melanomatosis, and anaplastic malignant melanoma. diagnosis generally involves a combination of clinical examination and laboratory techniques such as fine needle aspiration, histopathology, and immunohistochemistry. treatment options for equine melanocytic tumors vary widely. common methods include surgical excision to remove the tumor, chemotherapy to target cancer cells, and electroporation which employs electric pulses to enhance drug delivery directly into tumor cells. less frequently employed treatments include immunotherapy and radiotherapy. early intervention is crucial for managing these tumors effectively؛ untreated or delayed cases tend to grow larger and exhibit increased malignancy over time. horses with postponed tumor excision often develop multiple tumors. equine melanocytic tumors necessitate diligent management due to their potential progression from seemingly benign lesions to malignant cancers. a thorough understanding of their genetic underpinnings combined with timely diagnostic and therapeutic measures is essential for improving outcomes in affected horses. future research aims at identifying new therapeutic targets such as biomarkers like cd47, pd-1, and cox-2 that could pave the way for innovative treatment strategies.