Mutations in the breast tumor risk gene (BRCA1) make individual susceptible to tumors not only of breasts and ovar, but of many different origins. This is due to the role of BRCA1 in the DNA repair mechanisms.
A paper in Molecular Cell shows now an additional role for BRCA1: It is involved when the replication fork gets stuck at an interstrand cross which is likely to occur in the presence of the drug Cisplatin. With the help of BRCA1 the CMG helicases, which unwinds the strand to be replicated, are unloaded. Then DNA can be repaired and finally replicated faithfully.