Pastero Linda, Cotellucci Andrea
Università Degli Studi di Torino
Pathological mineralization can be thought of as a breakdown of biomineralization: biominerals in non-pathological conditions form only in some specific sites with well-defined chemistry, morphology and size distribution to fulfill a function, usually in cooperation with an organic matrix (take bones and teeth as the most representative examples).
In pathological conditions, mineralization occurs without specific control and function. While in the field of biominerals (and biomimetic materials), a lot of crystallographic literature has been published because of the interest of industries in mimicking natural functional materials, in the field of pathological mineralization, crystallography definitely plays a minor role.
In our work, we aim to provide a crystallographic interpretation of a particular case of pathological mineralization, well aware of the limitations induced by neglecting the influence of physiologic or organic variables and even more mindful of the importance of a multidisciplinary approach. To that end, we propose the first crystallographic approach to the interplay between calcium oxalate and calcium hydroxyapatite in breast carcinoma calcification, applying the basics of crystal growth and epitaxial relationships to pathological mineralization. Breast carcinoma is associated with mineralized deposits. These microcalcifications show specific features depending on the benign or malignant character of carcinoma.
Calcium oxalates are usually associated with benign diseases, while calcium apatite appears in benign and malignant cases. Moreover, Ca-apatite in breast carcinoma may show magnesium substitution, with the correlation between magnesium concentration in apatite and malignancy being unclear. Ca-oxalate (mineral whewellite) and Ca-hydroxyapatite precipitate in similar chemical conditions, being the local pH the controlling variable. We propose an epitaxial relationship between calcium oxalate and apatite as the primary mechanism controlling the seesaw appearance of the two in some chemical (and pathological) circumstances.
Moreover, since the contradictory results of the studies on the application of vitamin C to breast cancer treatment, we propose a mineralogic approach to the problem, finding calcium oxalate as the main crystal phase precipitating in the presence of vitamin C’s degradation cascade products.