Researchers use a dye to illuminate primary breast cancer tumour, lymph node spread in dogs
Scientists from the School of Veterinary Medicine at the University of Pennsylvania (Penn Vet), US, have demonstrated how a glowing dye can be used to light up breast cancer cells in dogs and would immensely help canine cancer treatment. This offers hope for improved cancer excision surgery outcomes in humans as well, as surgeons can cut and remove cancerous tissue more reliably and leave healthy tissues intact.
The new technique by the Penn Vet team centers on a safe, FDA-approved contrast agent called indocyanine green (ICG), which is known to allow cancerous tissue to be distinguished from healthy tissue under near-infrared light. The dye is thought to selectively accumulate in cancer cells because it seeps through the blood vessels in tumours, which are more leaky than those found in healthy tissue.
The team gave dogs with mammary tumours an injection of ICG the day before their surgeries and then inspected the extracted tumours, the original tumour site and the lymph nodes, to see how effectively the ICG illuminated the cancerous cells and whether they may have spread.
The team found that the larger tumours did indeed accumulate more dye. They also found evidence of cancerous cells in the lymph nodes where fluid from the breast drains to first. The results could be adapted for use in clinical settings for humans.
“In women with breast cancer and also in dogs with mammary cancer, its prognostic if the cancer has spread to the lymph nodes,” said veterinary surgeon David Holt. “What we showed was that we could identify both draining lymph nodes and lymph nodes with metastatic disease with this glowing dye.”
