Breast microcalcifications as biomarkers of tissue pathology

Breast cancer is the most commonly diagnosed cancer in women in the UK, accounting for 31% of all cases. Some breast malignancies, known as in-situ cancers, have the potential to form invasive cancer, but this is not true in all cases. There is significant overtreatment of in-situ cancers, which can be a traumatic process for patients. Therefore, a robust method to determine which of these malignancies will develop into clinically significant invasive cancer is required. Ductal carcinoma in-situ (DCIS), the most common in-situ breast cancer, has associated calcium deposits (microcalcifications) in 80-90% of cases. Microcalcifications are therefore an important diagnostic indicator of DCIS. These microcalcifications are composed of hydroxyapatite, a nano-crystalline calcium phosphate, with the potential for high levels of ion substitution.The crystalline nature of hydroxyapatite permits the use of X-ray diffraction to investigate the microstructure of microcalcifications found in breast tissue. X-ray diffraction patterns can be used to determine properties such as crystallite size, irregularities in the crystal lattice and give indications about the ions present. Together, differences in these parameters may permit the development of a novel prognostic marker for different breast tissue pathologies.