One of the El Paso Zoo’s Asian elephants, Juno, will undergo her seventh cancer treatment this week.

In October 2016, Juno was diagnosed with a malignant mass in her right mammary gland, commonly known as breast cancer. This is the only currently known case of breast cancer in an elephant; elephants are generally not diagnosed with cancer.  

Juno received her first three rounds of electro-chemotherapy in 2017 and 2018. The mass responded to treatments, and decreased in size. In October of 2019, December 2019 and February 2020, Juno was placed under general anesthesia to perform additional electro-chemotherapy treatments, along with a localized Interleukin 12 (IL-12) gene therapy treatment to enhance her immune system’s ability to recognize and fight the tumor. During the procedures, the tumor was infused with a chemotherapy drug and the IL-12 gene, then treated with a small electric pulse to drive the agents into the cancer cells.

These treatments carried out during the last four years, kept the tumor small and added to Juno’s quality of life. Unfortunately, the tumor has stopped responding to the last treatment and has become more aggressive. According to veterinary experts, surgical removal of the mass or hospice care and eventual euthanasia are the only options now available. Staff has decided to attempt surgical removal in a final effort to treat the cancer and prolong Juno’s life.

“We are asking the community to please keep Juno in your thoughts and trust the El Paso Zoo is doing everything in its power to heal her, make her comfortable and to give her many more years on this planet,” said El Paso Zoo Director Joe Montisano.

A board-certified veterinary surgeon who specializes in large animal surgery will perform the surgery along with zoo veterinarians assisting and managing Juno’s anesthesia and care during the procedure.

This procedure is considered high risk – surgery on this scale is uncommon in an elephant. Juno is 53 years old, which is considered geriatric for an elephant and there are many possible complications due to the nature of the surgery, her age and length of healing. Veterinary experts have advised Zoo staff that the cancer itself may have metastasized.

Cancer treatments for Juno are made possible by the support of the El Paso Zoological Society.