Secreted Frizzled-related protein 1 (SFRP1) encodes a member of a protein family that contains a cysteine-rich domain similar to the WNT-binding site of Frizzled receptors and regulates the WNT pathway. The WNT pathway is frequently altered in human cancers. We have de®ned the pattern of SFRP1 mRNA expression in the progression of breast cancer. We show that SFRP1 is expressed in the epithelial component of normal breast, in the in situ component of ductal carcinomas and is lost in more than 80% of invasive breast carcinomas except the medullary type. Loss of SFRP1 expression is correlated with the presence of hormonal receptors. Conversely, the maintenance of SFRP1 in carcinomas is correlated with the presence of lymphoplasmocytic stroma. No signi®cant association was observed between SFRP1 status and the level of apoptosis in tumoral cells. Oncogene (2001) 20, 5810 ± 5817.

Deletions and ampli®cations are frequent alterations of the short arm of chromosome 8 associated with various types of cancers, including breast cancers. This indicates the likely presence of tumor suppressor genes and oncogenes. In the present study, we have used the expressed sequence tag (EST) map of 8p11-21 to assemble a set of available cDNAs representing genes from this region. DNA arrays were prepared for expression analysis and search for genes potentially involved in breast cancer. Underexpresion in tumoral breast cells (versus normal breast) was observed for 15 transcripts. Among these, the Frizzled-related gene FRP1/FRZB, was turned o in 78% of breast carcinomas, suggesting that the lack of its product may be associated with malignant transformation. Overexpression in tumoral breast cells was observed for 13 genes. The FGFR1 gene, that encodes a tyrosine kinase receptor for members of the ®broblast growth factor family, was identi®ed as a good candidate for one ampli®cation unit. Taken together, our results demonstrate that such a strategy can rapidly identify genes with an altered pattern of expression and provide candidate genes for malignancies.

A panel of somatic cell hybrids specific for human chromosome 8 was used to localize 64 expressed sequence-tagged site (ESTS) markers to six individual regions by PCR amplification. Nine ESTS correspond to 8 known human genes and 6 others show similarities with vertebrate genes, whereas the remaining 49 ESTS markers correspond to novel genes with no database similarities. These gene transcript markers will contribute to the developing physical and expression maps of chromosome 8, and to the search for candidate genes for various human diseases.