MXD1 and neoplasm: In light of the observations of reduced MAD1 expression in Barrett's metaplasia and previous evidence of MXD1 repression in oesophageal adenocarcinoma (Hourihan et al, 2003), the trend towards upregulation of MAD1 in adenocarcinomas was not anticipated and would appear to be in conflict with the suggestion that MAD1 may have a role as a tumour suppressor (Ayer et al, 1993; Zervos et al, 1993; Cultraro et al, 1997; Queva et al, 1998).