Methods based on the detection of RAD51 foci in tumor cells

A method for the treatment of a cancer in a subject in need thereof, the method comprising the administration to said subject of a therapeutically effective amount of a PARP inhibitor agent, wherein the subject has been identified as responder to said PARP inhibitor agent by a method for predicting the response of a subject diagnosed with cancer to the PARP inhibitor agent which comprises:

• i) determining the level of cells with RAD51 foci in a sample containing tumor cells isolated from said subject wherein the subject has not received, within 24 hours prior to the isolation of the sample, a chemotherapy selected from the group consisting of AC, FEC, ECF and navelbine/epirubicin, and
• wherein the sample has not been treated with a method that induces DNA damage before determining the level of cells with RAD51 foci, and
• ii) comparing the level obtained in step i) with a reference value, wherein:
• a level of cells with RAD51 foci lower than said reference value indicates that the subject is predicted to respond to the PARP inhibitor agent, or
• a level of cells with RAD51 foci equal or higher than said reference value, indicates that the subject is predicted not to respond to the PARP inhibitor agent.