The myofibroblast, electron microscopy and cancer research

There is a dichotomy in the use of the term myofibroblast, which may compromise understanding this cell and its role in the detailed processes of normal tissue development and tumor invasion. There is an evolved and focused definition for this cell, which includes ultrastructural and molecular features, which contrasts with many of the cells in normal tissues, which have also been described as myofibroblasts but which differ significantly from the tumor stromal myofibroblast in possessing a lamina and other features not typical of the myofibroblast of tumor stromal type: the latter has cell surface fibrillar fibronectin, which has been characterized by electron microscopy especially and may have a role in processes pertinent to cancer cell invasion. Understanding the detailed steps in cell processes, whether of normal development or cancer cell invasion, might be enhanced by a comparably detailed definition, in which ultrastructure plays one part. © 2009 UICC.