<qa>  What will be used as a positive control?PR WB: Nuclear extracts will be performed and processed as described previously. T47D cells will be used as a positive control. Paola Rojas will be in charge of the determination of the PRAPRB ratio. Procedures will be recorded. Results will be sent to Dr.Liguori and Dr. Gass, and a copy of them will be kept in the CRF. 