Director's message: Individualizing cancer treatment

Vol. 3, Issue 1, 2014

Summary

Genome-guided therapeutic trials offer new hope.

Photograph showing Robert B. Diasio, M.D., director, Mayo Clinic Cancer Center

Robert B. Diasio, M.D.

People often ask me if there is reason for hope in developing new cancer treatments. Increasingly, my answer is, "Yes, there is definitely reason for optimism."

With the availability of more comprehensive human genome data from sources such as The Cancer Genome Atlas, clinicians are now able to rapidly and inexpensively sequence an individual patient's tumors. The result is new opportunities for researchers to conduct therapeutic trials for many types of cancer.

The Mayo Clinic Cancer Center took its first steps in this direction nearly two years ago when we launched our first genome-guided protocol in a neoadjuvant trial for newly diagnosed breast cancer patients.

The Breast Cancer Genome-Guided Therapy study, or BEAUTY study, helps physicians tailor chemotherapy to breast cancer patients based on their individual genomes and the genomes of their tumors. Physicians obtain three whole-genome sequences — one from the patient's healthy cells before treatment, one tumor genome before chemotherapy and one tumor genome after.

In phase I of the BEAUTY study, researchers are studying participants to look for common mutations that allow some tumors to adapt and thrive during chemotherapy. This information helps doctors identify new targets for potential drug development and treatment strategies.

Women diagnosed with high-risk cancers have their healthy genome and breast cancer cells sequenced before treatment and then receive the commonly prescribed chemotherapy to shrink the tumor.

After surgery, the patient's residual cancer cells are sequenced to evaluate how they have mutated and adapted to chemotherapy.

In addition, we are propagating each patient's tumor tissue by implanting cell lines in immune-compromised mice before and after chemotherapy. By using these so-called mouse avatars, researchers are able to study the effects of both approved and new anti-cancer drugs, alone and in combination, on tumors of individual patients and to identify the best treatment without risk of harm to the patient since the medications are used on the mouse avatars.

We have just launched a similar approach for prostate cancer, and we plan to extend this approach to other malignancies.

Yes, there is reason for optimism.

Robert B. Diasio, M.D.
Director, Mayo Clinic Cancer Center
William J. and Charles H. Mayo Professor