c-Fos expression is elevated after treatment with HXR9. SK-OV3 and OV-90 cells were incubated for 24 hours with 120 μM HXR9 or CXR9 and cFos expression was analysed by RT-QPCR. RNA was also extracted from SK-OV3 tumours excised from mice treated twice weekly with HXR9 (10 mg/Kg)iv, after an initial dose of 100 mg/Kg iv on day 3. Results are presented as a ratio with beta-actin expression (x1000). A very high increase in transcription of c-Fos in HXR9 treated SK-OV3 cells and tumours was observed. Error bars represent the standard error of the mean for three independent experiments (cell lines) or for three tumours (in vivo model).