Vibrational spectroscopic analysis of breast calcifications and surrounding tissue

Abstract

Breast calcifications can be found in both benign and malignant lesions and the composition of these calcifications can indicate the possible disease state. Calcium oxalate dihydrate (COD) is found to be associated with benign lesions, however calcium hydroxyapatite (HAP) is found mainly in malignant tissue. As current practices such as mammography and histopathology examine the morphology of the specimen, they can not reliably distinguish between the two types of calcification, which frequently are the only features that indicate the presence of a cancerous lesion. Therefore this information can be used to make a simplistic diagnostic decision, if the biochemistry of the calcifications can be probed. Studies have been performed utilising the synchrotron mid-IR beamline at Daresbury (UK) to probe the local tissue biochemistry around breast calcifications. Raman and FTIR spectroscopic analysis of the same specimen have also been performed and spectral maps have been collected of areas in and around calcifications. Principal component analysis was used to identify the major differences in the spectra across each map. FTIR and Raman spectroscopic techniques provide complementary biochemical information and demonstrate great potential for determining biochemical changes in calcified breast tissue. Further studies will be carried out using these techniques to investigate the formation mechanisms and effects of hydroxyapatite on breast tissue and to correlate the type of hydroxyapatite present to the tumour grade.