Exploring the biochemical composition, heterogeneity and potential implications of breast microcalcifications with Raman spectroscopy for the prognosis of Ductal Carcinoma in Situ

Ductal carcinoma in situ (DCIS) is regarded as a potential precursor to breast cancer. The molecular pathway that drives the progression of DCIS to the subsequent invasive ductal carcinoma (IDC) is still unclear, leaving clinicians struggling to delineate the real extent of DCIS and thus the treatment strategy to adopt. Therefore, understanding the DCIS trajectory will prevent overtreatment of this disease. This study emphasizes the diagnostic and prognostic value of Microcalcifications (MCs), abnormal calcium deposits in the mammary gland, whose mineral composition is related to different degrees of pathology. MCs are associated with 75-90% of all cases of DCIS, as well as some high-risk invasive cancers, with a poorer patient prognosis reported in some cases. Several studies highlight that MCs may play an active role in mitogenesis, upregulation of gene expression and enhanced invasion of surrounding tissue, affecting the entire cellular behaviour. To address the challenges posed by DCIS overtreatment and improve the prognostic value of MCs, this study combines Raman spectroscopy with robust analytical approaches such as k-means clustering analysis (KMCA), principal component analysis (PCA), and analysis of variance (ANOVA). The integration of these techniques provided valuable insights into the compositional properties of various phases of calcium phosphate (CaP) minerals found within MCs, thereby shedding light on the physicochemical nature of MCs present in the ducts of malignant breast tissue. Importantly, this research successfully identified significant spectral variations associated with different degrees of DCIS aggressiveness. Subtle alterations observed in MCs spectral profiles enabled the discrimination between DCIS lesions associated with favourable and unfavourable prognoses. The findings of this study emphasize the tremendous potential of Raman spectroscopy as a non-invasive and label-free prognostic tool, capable of accurately predicting the clinical outcome of breast cancer. By providing valuable insights into the spectral profiles of MCs, Raman spectroscopy offers a promising avenue for enhancing breast cancer risk assessment, reducing overtreatment, and enabling early intervention in high-risk cases