Most cancer research relies on laboratory mice that have been genetically engineered or chemically treated to develop tumors. But these artificial models do not always capture how cancer behaves in the real world. A team led by Dr. Ylenia Chiari at the University of Nottingham has turned to a surprising alternative: a popular pet reptile that develops cancer naturally and frequently.
The lemon frost leopard gecko (Eublepharis macularius) is a white-and-yellow color morph that emerged from a spontaneous genetic mutation during selective breeding. The striking appearance made it a hit in the pet trade, but breeders soon noticed a troubling pattern: a high proportion of these geckos developed iridophoromas — aggressive, often metastatic tumors of the pigment cells. The tumors can recur after removal and spread to internal organs, closely resembling the behavior of malignant melanoma in humans.
The research team performed whole-genome sequencing on tumor and healthy tissue from the same animals, comparing the genetic profiles to identify the specific mutations driving the cancer susceptibility. The results, published in BMC Biology, revealed that the affected genes and biological pathways are not unique to reptiles. Many of the same genetic changes are known to play critical roles in human oncology — including disruptions in cell-cycle regulation, DNA repair mechanisms, and signaling pathways that control cell growth and division.
One surprising finding is that the lemon frost gecko's tumors arise from a single ancestral mutation that spread through the captive breeding population, meaning every affected gecko carries the same genetic predisposition. This makes the population a natural experiment in how a cancer-predisposing mutation propagates and expresses itself across genetically diverse individuals — something impossible to replicate in a laboratory setting.
Dr. Scott Glaberman of the University of Birmingham, a co-author of the study, emphasized the broader significance: "By studying both animals that are vulnerable to cancer and those that resist it, we have far greater power to understand the disease itself. This is one of the many reasons why protecting biodiversity is so important." Some reptiles, such as turtles and tortoises, exhibit remarkable natural resistance to cancer, and comparing the two extremes may reveal strategies for prevention and treatment.
The findings also demonstrate the power of applying genomic tools originally developed for human cancer research to diverse organisms. Brandon Hastings, a PhD researcher and co-author, noted that looking "across the tree of life in search of answers" can yield insights that would be impossible to obtain from traditional models alone.
Knowledge takeaway: The lemon frost leopard gecko, which develops aggressive metastatic tumors in 80% of individuals due to a single ancestral mutation, shares genetic pathways with human cancers — providing a natural model for studying how cancer initiates, evolves, and spreads across a genetically diverse population.