Microcalcifications in breast cancer: Exploring their molecular formation and biological significance

MCT Research Talks – 23th January 2017

Survival rates for breast cancer have risen significantly over the past few decades, in large part due to a considerable increase in the number of tumours detected via mammography at an early, more easily-treated stage. The presence of microcalcifications on a mammogram constitutes an important diagnostic clue to radiographers, with approximately 30% of invasive breast tumours and up to 90% of cases of ductal carcinoma in situ (DCIS) being detected by the presence of calcifications. Some studies have also suggested that the presence of calcifications may act as a prognostic factor, as patients presenting with breast tumours with associated calcifications have a worse prognosis than those without.
Despite their importance in breast cancer diagnosis, the exact mechanism by which microcalcifications are formed remains largely unexplored. Our group previously established the first in vitro model of mammary cell microcalcification (1) which we have recently extended to the human the breast cancer cell line MDA-MB-231. When cultured with a cocktail of osteogenic-reagents for a prolonged period, these cells produce deposits of calcium phosphate.

Figure 1. Alizarin Red S stained MDA-MB-231 cell monolayer, grown in DMEM (Control) or DMEM supplemented with osteogenic cocktail and dexamethasone (OC+Dex). Red staining indicates presence of calcified deposits.

Using a combination of histological staining, quantitative measurement of calcium content, alkaline phosphatase activity and analysis of gene expression, we can monitor the changes in cell phenotype leading to onset of mineralisation. The nature of our model allows for easy manipulation of cell culturing conditions and by adding various inhibitory compounds or cytokines to our culture media, we can identify the key pathways and targets necessary for calcification production. In doing so, we hope to build up a comprehensive understanding of the cellular and molecular basis underlying the formation of these important diagnostic clues.

Recommended reading:

Cox RF, Hernandez-Santana A, Ramdass S, McMahon G, Harmey JH, Morgan MP.  Microcalcifications in breast cancer: novel insights into the molecular mechanism and functional consequence of mammary mineralisation. Br J Cancer. 106(3):525-37 PMID: 22233923 (Jan 2012)

Shane O’Grady, Maria Morgan