The most common type of ovarian cancer is more deadly if it consists of a patchwork of different groups of cells, according to a Cancer Research UK study published in PLOSMedicine.
Serous ovarian cancers containing a variety of genetically-different cells were more likely to become resistant to treatment and come back again than cancers made of more similar cells. Women with this type of tumour also died sooner than those with less varied tumours.
The scientists, from the Cancer Research UK Cambridge Institute, Cambridge University and Addenbrooke’s Hospital, analysed DNA from 135 samples of serous ovarian cancers from 14 patients having chemotherapy. The team is the first to measure the genetic variety – called tumour heterogeneity – in a solid tumour and link this to cancer survival.
Tumour heterogeneity begins as tumours evolve from a single damaged cell, which quickly changes and develops into a patchwork of different cell groups. Each patch of cells contains a similar but distinct set of DNA errors, so can look and behave differently from other cell clusters. This makes treating the disease more challenging, with some groups of tumour cells being more resistant to chemotherapy than others.
Lead researcher Dr James Brenton, from the Cancer Research UK, Cambridge Institute, said: “Our research is important because it helps make sense of the genetic chaos inside tumours. It’s another step closer to cracking the code on cancer biology so that we can understand sooner how patients will respond to treatment – and how to develop better drugs for this hard to treat cancer in the future.”
The team also found that gene faults contributing to drug resistance were present in some parts of tumours before treatment began, replacing the previous belief that chemotherapy caused these genetic changes.
