Brillouin microscopy is featured on the front cover of BioPhotonics, highlighting its growing role in cancer research. The article showcases recent work from the Taubenberger group at TU Dresden, using Brillouin imaging to study breast cancer spheroids in 3D hydrogels. Unlike traditional methods, this noninvasive approach preserves the native environment of tumor cells, revealing how mechanical properties—like increased deformability—may correlate with metastatic potential.