Desmosomes and cancer.

Desmosome expression is downregulated in poorly differentiated transitional cell carcinomas and squamous cell carcinomas of the head and neck. In these tissues, desmosomes may have an invasion and metastasis suppressor function. In colorectal carcinoma, no downregulation is found. This raises the question of how tumours possessing intact desmosomes can invade and metastasize. Temporary modulation of adhesive affinity may be a possible mechanism. Desmosomes are widely distributed in epithelia and other tissues and desmoplakins are expressed in all. Thus, antibodies to desmoplakins are very reliable markers for immunohistochemical diagnosis of carcinomas. Intracranial tumours can also be distinguished because meningiomas possess desmosomes and vimentin intermediate filaments, but metastatic carcinomas possess desmosomes and keratin.