Microcalcifications in breast cancer tissue studied by X-ray absorption, emission, scattering and diffraction

Microcalcifications (MC) are observed in various tissues and in relation to several diseases. For breast cancer, recent studies have reported differences in the nature of the MC and correlations to the degree of malignancy of the neoplasm. Here, investigations of benign, ductal carcinoma in situ (DCIS) and invasive ductal carcinoma (IDC) breast MC using X-ray fluorescence, X-ray absorption spectroscopy and wide-angle X-ray scattering are reported. While Mg has been observed in all MC, only for the benign MC has a rim of crystalline whitlockite been identified as a minor crystalline phase in addition to the major hydroxyapatite (HAP) one. MC in DCIS and IDC tissue exhibit a higher abundance of a high-crystallinity HAP phase in comparison with the less well ordered MC in the benign tissue. Moreover, the distribution of other trace elements in the MC, such as Na, S, Cl, Sr and Y, is observed. For the quantitative analysis of the elemental maps, the experimentally determined sample thickness in each pixel has been incorporated as an additional parameter in the fitting process to account for sample roughness.