Researchers made this “completely unexpected” finding while seeking to explain why cancer cells are so resilient inside the human body when they are easy to kill in the lab.
For the study, the researchers tested the effects of a type of chemotherapy on tissue collected from men with prostate cancer, and found “evidence of DNA damage” in healthy cells after treatment. Chemotherapy works by inhibiting reproduction of fast-dividing cells such as those found in tumours.
They found that healthy cells damaged by chemotherapy secreted more of the protein WNT16B, which boosts cancer cell survival. The protein was taken up by tumour cells neighbouring the damaged cells.
“WNT16B, when secreted, would interact with nearby tumour cells and cause them to grow, invade, and importantly, resist subsequent therapy,” said the study co-author Peter Nelson of the Fred Hutchinson Cancer Research Centre in Seattle.
In cancer treatment, tumours often respond well initially, followed by rapid regrowth and then resistance to further chemotherapy.
“Our results indicate that damage responses in benign cells… may directly contribute to enhanced tumour growth kinetics,” wrote the team.
The researchers confirmed their findings with breast and ovarian cancer tumours.