RAPH1 and major depressive disorder: High RAPH1 expression is associated with an aggressive breast cancer phenotype and has independent prognostic value (31); RAPH1 was recently found to be critical for regulating cell proliferation, as it stimulates extracellular matrix (ECM) stiffness-mediated cyclin expression and intracellular stiffening in mouse embryonic fibroblasts, although increased ECM stiffness leads to abnormal cell cycle progression and proliferation (32); high expression of RAPH1 can be used as a marker of major depressive disorder (MDD) (33).