SYDNEY, May 12 (Xinhua) -- Scientists in Australia have identified a hidden mechanism explaining why some breast cancer can return many years after successful treatment, offering a potential new target to prevent relapse.
Researchers at Australia's Garvan Institute of Medical Research have mapped the drivers of breast cancer cells that resist therapy by growing extremely slowly rather than entering a completely dormant state, said a Garvan Institute statement released Tuesday.
The research revealed rogue cells that change their programming to allow them to divide at a remarkably slow pace, meaning they could form microscopic tumours that silently develop in distant organs, evading detection for decades, the statement said.
This research addresses a major challenge for patients with estrogen receptor-positive breast cancer, where the possibility of relapse can linger for years after being declared cancer-free, it said.
Relapse is known to occur when dormant cancer cells in bone or other organs "wake up" and metastasize. The new research, published in Nature Communications, identifies a parallel pathway in which stealthy cells form secondary tumours, suggesting new approaches to prevent metastasis.
Though slow-growing, these cancer cells are far from harmless. Once their "micrometastases" become detectable or disrupt vital organs like the brain or bone, they can turn into life-threatening, chemotherapy-resistant relapses, researchers said.
They found that some cells naturally divide very slowly under treatment, inadvertently protecting themselves. As therapy eliminates fast-growing cells, these slow-growing survivors remain and can later cause relapse.
The team identified a cellular communication channel known as the Rac1 pathway as a key driver of these slow-growing cells' survival and movement. They demonstrated that blocking this pathway could effectively shrink the cancer. ■
