Tumor fragments collected from patients can now serve as the starting point for hundreds of models grown in the laboratory.
An international team has developed nearly 700 of them, covering 25 types of cancer. This collection should allow scientists to test treatment approaches more broadly on cells that remain close to human cancers.
To study a drug before human trials, laboratories often use cancer cells capable of multiplying for long periods. The problem is that the available cell lines represent only part of the diversity observed in patients. Some rare cancers, genetic profiles, or treatment-resistant forms are therefore much harder to reproduce.
The new collection starts directly from tumor samples obtained from patients. Scientists sought to grow these cells and then establish models that could be used repeatedly. The result greatly expands the options available for comparing the behavior of different cancers under controlled conditions.
This diversity matters greatly.
Two tumors located in the same organ can in fact respond very differently to a drug. Their DNA may contain distinct alterations that change their growth or sensitivity to treatment. With numerous models available, teams can investigate which profiles respond to a molecule and which resist it, rather than drawing conclusions from a few widely used cell lines.
These cells can also be used to search for weaknesses specific to each tumor. Scientists can, for example, disrupt certain genes and observe whether the cells continue to multiply. When a cancer cell depends heavily on a particular gene to survive, this dependency may become a lead to investigate when designing a future targeted treatment.
The collection is also valuable because it is shared. The models are intended to be accessible to the international scientific community, along with information about their characteristics. Several laboratories will therefore be able to work on the same references, compare their results, and select models suited to a specific question without having to recreate the entire collection.
These cultures nevertheless replace neither a real tumor in the body nor clinical trials. Cancer interacts with blood vessels, the immune system, and many neighboring cells—elements that a cell culture cannot fully reproduce. A drug that is effective on these models must still pass through several stages before it can be offered to patients.
The next step notably involves using this resource on a large scale to link the genetic characteristics of tumors to their responses to drugs. The models must also join the resources used by the Cancer Dependency Map, a program that seeks to map exploitable weaknesses in different cancers.