Adhesion molecule expression in breast cancer: the phoenix in tumour metastasis?

Adhesion molecules have a number of diverse roles, amongst which is the con trol of tissue architecture and the maintenance of tissue integrity, Most t umours have an abnormal architecture and loss of tissue integrity is though t to be an important step in the development of local invasion. Thus, alter ations in adhesion molecules may have a role in both tumour development and tumour invasion. The role of these molecules in the establishment of tumou r metastases is much less certain. The tumour cells in a metastatic deposit are in a different environment and are faced with a different set of selec tion pressures, which may drive tumour evolution in a new direction. Metast atic deposits often resemble the tumour of origin and not infrequently show better differentiation. Together with evidence from experimental maintenan ce systems which shows that maintenance of intercellular contact may preven t apoptosis, this implies a role for adhesion molecules in tumour metastasi s. Copyright (C) 2000 John Wiley & Sons, Ltd.