One of the things that makes cancer so difficult to ‘cure’ is that it has so many forms. Perhaps most difficult of all, as scientists are learning, are cancers such as the most common and usually fatal brain cancer glioblastoma multiforme (GBM). As a new study at the University of North Carolina (Chapel Hill, USA) has shown, this cancer has not one but four different sub-forms, which may be active simultaneously. So instead of treating one cancer, now four must be considered.
The main work of the research used gene expression profiling – the measurement of activity for thousands of genes at the same time – to distinguish between cells, showing that there was indeed more than one type of cancer cell at work, and that each had its own genetic and development pathways.
“Previous work has established that gene expression profiling can be used to identify distinct subgroups of GBM,” says senior study author, D. Neil Hayes from the Division of Hematology/Oncology at the University of North Carolina at Chapel Hill. “However, the exact number and clinical significance of these was unclear.”
The researchers also report that the nature of these events indicate that the underlying disease process for each subtype may involve distinct cells of origin at a specific stage of differentiation.
The clinical significance of this discovery is the obvious necessity to re-think treatments, especially chemotherapy, to address the four sub-types of GBM individually. For research, the further questions are when and how these four types arise? Are there connections (signaling) between them? Many of the answers will come from examining the tumor cells in more detail at the molecular level. As is often the case with cancer, the more scientists uncover, the more complicated the picture becomes.