Mechanical properties of breast, kidney, and thyroid tumours measured by AFM: relationship with tissue structure

The mechanical properties of the extracellular matrix are essential for regulating cancer cell behaviour, but how they change depending on tumour type remains unclear. The aim of the current study was to determine how the mechanical properties of tumours that frequently metastasize to bones were affected depending on histological type. Human breast, kidney, and thyroid specimens containing tumour and normal tissue were collected during surgery. The elastic modulus and elastic fraction of each sample were characterised using atomic force microscopy and compared with histopathological markers. We observed that tumour mechanical properties were differentially affected depending on organ and histological type. Indeed, clear cell renal carcinoma and poorly differentiated thyroid carcinoma displayed a decrease in the elastic modulus compared to their normal counterpart, while breast tumours, papillary renal carcinoma and fibrotic thyroid tumours displayed an increase in the elastic modulus. Elastic fraction decreased only for thyroid tumour tissue, indicating an increase in viscosity. These findings suggest a unique mechanical profile associated with each subtype of cancer. Therefore, viscosity could be a discriminator between tumour and normal thyroid tissue, while elasticity could be a discriminator between the subtypes of breast, kidney and thyroid cancers