Cataloging breast cells to find cancer origins

Breast tissue is made up of a variety of cells, including epithelial cells (pink), immune cells (cyan), and fat cells (black), that are visible in this cross-section of a mouse mammary gland. CSHL Associate Professor Camila dos Santos’s team identified and cataloged thousands of human and mouse breast cells to help understand the origins of breast cancer. Photo credit: Labor Camila dos Santos / dos Santos, CSHL / 2021

What if you could predict which cells could become cancerous? Breast tissue changes dramatically over the course of a woman’s life. This makes it especially difficult to find markers of sudden changes that can lead to cancer. Cold Spring Harbor Laboratory (CSHL) associate professor Camila dos Santos and her team identified and cataloged thousands of normal breast cell types from humans and mice. The new catalog redefines healthy breast tissue so that if something goes wrong, scientists can pinpoint its origin.

Any breast cell can become cancerous. Dos Santos says:

“To understand breast cancer risk, you need to understand normal breast cells first. So when we think about preventive and even targeted therapies, you are preventing the right types of cells from developing into cancer cells.”

A traditional way to catalog cells is to keep track of some signature genes that are related to the function of the cell. To classify the cells more fully, the dos Santos team turned to a technique known as single-cell RNA sequencing. They tracked the activity of several genes in over 15,000 cells in mouse and human breast tissue. Samantha Henry, a Stony Brook University student in Dos Santos’ laboratory, says:

“We really did a whole catalog of many genes for each cell population to better define them. And when I say there were a lot of genes, there were a lot of genes and it took a long time to get them done.”

One group of cells comprised estrogen receptor positive cells that are generally amenable to treatment. However, the dos Santos team found that this group can be broken down into multiple subpopulations, each of which may respond differently to therapies.

Working with computational biologist CSHL professor Adam Siepel and his team, the team found that mice and human breast cells have similar genetic profiles, which shows why studies on mice are likely to be relevant to humans. Marygrace Trousdell, a computer science developer at the dos Santos laboratory, says:

“We always have problems with the final classification of certain cell types. Sometimes I think I’ve seen every gene out there and then something else shows up.”

Currently, the lab is trying to differentiate normal genetic shifts from those associated with cancer. Dos Santos hopes their catalog of breast cell types will reveal what types of cells to monitor and guide researchers on future treatment options.

New cell atlas shows healthy and cancerous breast tissue

More information:
Samantha Henry et al., Characterization of Gene Expression Signatures to Identify Cellular Heterogeneity in the Developing Mammary Gland, Journal of Mammary Gland Biology and Neoplasia (2021). DOI: 10.1007 / s10911-021-09486-3 Provided by the Cold Spring Harbor Laboratory

Quote: Cataloging of Breast Cells to Search for Causes of Cancer (2021, May 14), accessed May 15, 2021 from

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