Probing what calcium deposits do and don’t reveal about breast cancer
Calcium phosphate, also known as apatite, is the body’s most abundant mineral. It’s best known for making up bones and teeth, and for showing up on X-rays.
When tiny apatite formation show up a particular low-energy X-ray called a mammogram, they can provide early hints of abnormalities. But whether they’re benign or malignant has been hard to pin down.
“They are a common finding within the tumor, but whether they are a byproduct or whether they are in some way involved in the pathology, we don't really know that,” said co-author Dr. Daniel Sudilovsky of Kingman Regional Medical Center.
A new paper in the journal Science Advances by researchers from Cornell University and Memorial Sloan Kettering Cancer Center, both in New York, could change that.
“This paper actually starts to kind of dig into that question a little more than others have,” said Sudilovsky, who also has appointments at Yuma Regional Medical Center and Western Arizona Regional Medical Center in Bullhead City.
Prior research, based on bulk chemical analyses, suggested calcium-phosphorus ratios might correspond to certain cancers and outcomes.
“They would basically take big areas of tumor and big areas of benign tissue, and sort of grind them up, and then analyze the chemistry of that ground-up tissue,” said Sudilovsky.
“The difference with our study is that we very meticulously mapped out very small microcalcifications, both within cancer, in tissue next to cancers, in benign tissues, and in a variety of different benign processes in the breast,” he added.
Using these non-destructive maps, the authors found the relationships between diagnosis, prognosis and calcium-phosphorus ratios didn’t hold up.
“We didn't really see the same pattern when we individually isolated crystals in different environments,” said Sudilovsky.
Instead, they found new signatures: one involving trace metals like zinc, iron and aluminum; another entailing the ratio of proteins to oils and fats called lipids.
Sudilovsky says findings offer new targets for screening.
What’s more, because they represent an endpoint of metabolism, researchers might be able to work backwards to find cancer precursors.
“When we have high grade disease, they look this way; with lower grade disease, they look a different way,” said Sudilovsky. “Is there something that we can pinpoint genetically or at the protein level that is consistently creating this type of mineral in that environment? That could be a target.”