Expression of β-dystroglycan is reduced or absent in many human carcinomas

Aims: Dystroglycan is an important structural and signalling protein that is expressed in most human cells. α-Dystroglycan has been investigated and found to be reduced in human cancers, but there is only one published study on the expression of β-dystroglycan in human cancer and that was only on small numbers of breast and prostatic cancers. The aim was to conduct a comprehensive immunohistochemical survey of the expression of β-dystroglycan in normal human tissues and common cancers. Methods and results: Triplicate tissue microarrays of 681 samples of normal human tissues and common cancers were stained using an antibody directed against the cytoplasmic component of β-dystroglycan. β-Dystroglycan was strongly expressed at the intercellular junctions and basement membranes of all normal human epithelia. Expression of β-dystroglycan was absent or markedly reduced in 100% of oesophageal adenocarcinomas, 97% of colonic cancers, 100% of transitional cell carcinomas of the urothelium and 94% of breast cancers. In the breast cancers, the only tumours that showed any retention of β-dystroglycan expression were small low-grade oestrogen receptor-positive tumours. The only cancers that showed retention of β-dystroglycan expression were cutaneous basal cell carcinomas. Conclusions: There is loss or marked reduction of β-dystroglycan expression (by immunohistochemistry) in the vast majority of human cancers surveyed. Since β-dystroglycan is postulated to have a tumour suppressor effect, this loss may have important functional significance. © 2008 The Authors.