"Ovarian cancers are typically diagnosed when the disease is at an advanced stage and the tumor mass is often large with numerous metastases throughout the abdominal cavity," said Wigard P. Kloosterman, a principal investigator at the University Medical Center Utrecht and lead author of the study. "Following primary debulking surgery, we obtained a large number of samples from each of these women, which enabled the study of intra-tumor heterogeneity before chemotherapeutic or other drug treatments were applied. The current study, representing the most comprehensive data set to date, reveals extensive heterogeneity, which is probably one of the reasons this disease is so difficult to treat."
The study did reveal marked gene expression differences between tumor biopsies from the same patient. These include altered expression of WNT, integrin and Hedgehog pathway members in subsets of tumor biopsies. Currently, targeted therapies for ovarian cancer patients are being developed and proper patient stratification is essential for successful treatment. For example, application of Hedgehog pathway inhibitors is an emerging strategy that could only prove useful in those patients displaying changes in Hedgehog signaling. The results from this study suggest that fine-tuning of patient stratification for targeted therapy would require analysis of multiple biopsies per patient.
"This study is a key first step in the community's effort towards personalized medicine, one in which we characterize the mutational landscape within an individual's cancer," said Timothy Harkins, a Dir
|Contact: Suzanne Clancy|