Fas (APO-1/CD95) is a transmembrane receptor protein involved in cell
death signaling. Fas receptor and ligand are both expressed in breast
cancer cells, however these cells are resistant to apoptosis. Fas gene
mutations were detected in hematological and solid tumors, while
overexpression of a soluble Fas isoform in serum was related to cancer
stage and prognosis. In this work, direct sequencing of exons 6 and 9 of
the Fas gene from 90 patients did not reveal any structural alterations.
Moreover, no decrease was found in the ratio of the corresponding mRNA
species of transmembrane versus soluble Fas isoforms in 31 breast cancer
samples compared to 14 controls. Therefore, inhibition of Fas-mediated
apoptosis may not be due to structural alterations in the critical exons
6 and 9 of the Fas gene or a shift of expression towards the soluble Fas
isoform, but to other mechanisms operating in breast cancer cells. (C)
2003 Elsevier Science Ireland Ltd. All rights reserved
