Selective oestrogen receptor modulators (SERMs) are compounds with a mixed 
agonist/antagonist activity on oestrogen receptors. An ideal SERM is a compound 
with an oestrogen antagonist effect on the breast and uterus but oestrogen 
agonist effect on bone. Beside tamoxifen, a group of well-investigated SERMs is 
represented by raloxifene, LY-353381 (SERM3), EM-800 and CP-336156. On an 
empirical basis, tamoxifen has been used to pharmacologically treat desmoid 
tumours. Recently, raloxifene, a second-generation SERM, has been used in the 
treatment of familial adenomatous polyposis patients affected by desmoid tumour. 
The mechanisms through which these molecules affect desmoid tumour growth appear 
to be due, in part, to the fact that SERMs may act independently of oestrogen 
receptors. The knowledge of the molecular basis of SERM action will make the 
development of novel synthetic compounds with engineered tissue selectivity 
possible.