Unveiling Breast Cancer Origins: Cancer-Like Mutations Found in Healthy Cells

Unveiling Breast Cancer Origins: Cancer-Like Mutations Found in Healthy Cells

November 21, 2024 Catherine Williams - Chief Editor Health

Researchers from the University of British Columbia (UBC), BC Cancer, Harvard Medical School, and Memorial Sloan Kettering Cancer Center (MSK) have discovered early genetic signs of breast cancer. They found cancer-like mutations in the cells of healthy women.

The study analyzed over 48,000 breast cells from women without cancer. Most of the cells appeared normal. However, about 3% of the women had some breast cells with genetic changes linked to cancer.

The findings, published in Nature Genetics, indicate that these rare genetic changes may represent initial steps toward breast cancer. “It’s striking to see cancer-like mutations happening silently and at low levels in healthy women,” said Dr. Samuel Aparicio, a lead author of the study. He noted that while these mutations might not be harmful alone, they could lay the groundwork for breast cancer. Further studies could lead to new preventive strategies and early detection methods.

The identified mutations, called copy number alterations, involve the gain or loss of large DNA sections. Normally, the body repairs these changes, but if not detected, they can accumulate and lead to cancer.

To understand the prevalence of these alterations, researchers examined thousands of breast cells from 28 women using advanced gene sequencing technology.

Luminal cells, thought to be the origin of major breast cancer types, were specifically studied. “These genetic alterations accumulating in luminal cells suggest they may lead to cancer,” said Dr. Joan Brugge, a co-senior author. This work is an important step in understanding early events in breast cancer.

Most mutated cells had one or two alterations. However, some women with high-risk genetic variants BRCA1 and BRCA2 had cells with six or more alterations. These cells may indicate a progression toward cancer in high-risk individuals.

The researchers used a method designed for studying genome instability in cancer, allowing them to see rare genetic changes that standard tests often miss. This study raises new questions about how mutations accumulate and develop, and why they occur in luminal cells.

Understanding these processes could improve cancer risk assessment and management in high-risk individuals.

The study’s first authors included Vinci Au, Dr. Michael Oliphant, and Dr. Marc Williams. The project received support from organizations like the Gray Foundation and the US National Cancer Institute.