Public Repository of Biopsy Tissue May Improve Cancer Treatment

The Dana-Farber Cancer Institute has created a public repository of biopsy tissue collected from patients with leukemia and lymphoma.

The repository also has material from bone marrow, peripheral blood, and lymph nodes of mice. Information about the patient, cancer type, and characteristics of the tumor are all available.

The Public Repository of Xenografts (PRoXe) can be accessed by researchers all over the world due to its web portal, according to a report published by Cancer Cell. The purpose of PRoXe is to limit the amount of failed experimental drugs in early trials.

Currently in pre-clinical trials, researchers are testing the drugs against cancer cells in a petri dish, but these cells do not show how tumors behave in the body.

Mouse models with genetic mutations to mimic human cancers can be used in these trials, as well. These genetically modified mice are only available for only a few types of cancer.

Transplanting human cells into a mouse is called a patient-derived xenograft (PDX) model. These trials are more readily available because of PRoXe.

"About 90% of compounds that show anti-cancer activity in pre-clinical tests don't work when given to patients,” David Weinstock, MD said in a press release. “By trying drugs in PDX models, we can 'mimic' large and expensive human clinical trials and get answers about efficacy more quickly, less expensively and without the need for patients to get investigational drugs that won't work.”

Researchers who register with PRoXe can search the PDX models for specific subtypes of blood cancer. The researchers can have the cells shipped so they can be implanted into mice.

Human cancer cells have a high success rate of implanting into mice due to their lack of a defensive immune system. To show how their system worked, researchers tested an experimental drug for a type of leukemia called B-ALL.

One group of mice had a mutated TP53 tumor suppressor gene, while the other group had a normal gene. The results showed that mice with the normal gene had a higher survival rate than those with a mutated gene.

Researchers concluded that the drug should be tested in patients who have been treated for B-ALL and have a normal P53 gene. One limit of the PDX system that researchers noted is that blood cancers are significantly easier to transplant than solid tumors making it more feasible to repeat many times.