Via the Buck Institute Science of Aging blog, here is a look at the work of a scientist who specializes in the intersection of the stem cell and aging fields, an area that includes cancer and regenerative research:
Hematopoietic stem cells regenerate over a person's lifetime and can differentiate into all the different blood cell types found in humans, such as T-cells and B-cells. In principal, the hematopoietic stem cell population can regenerate from a single cell. So in theory a single transplanted cell can repopulate the pool. We have tried to do this in the hematopoietic system of old mice by taking hematopoietic stem cells from young mice and transplanting them into old mice, and the result was disappointing. The new stem cells did not integrate well and the aged in vivo environment did not allow for the newly introduced stem cells to function properly. In terms of using induced pluripotent stem cells (IPS cell) there are additional risks involved. IPS cells can transform and become cancerous, and they need to be generated and differentiated in culture, which is both time consuming and costly. I think trying to better understand why endogenous stem cells stop functioning and then adjusting the environment in vivo to keep them active, is a promising alternative avenue of treatment.
Studies have shown that stem cells are often the origin of many cancers. Due to their long lives and high replication rate, when compared to somatic cells, stem cells have an increased risk of acquiring DNA mutations that can cause cancer and other diseases. When studying hematopoietic stem cells, it is possible to isolate them from a simple blood sample. These cells can then have their DNA sequenced for possible mutations that might lead to cancer. With a better understanding of these mutations, new cancer treatments that are genetically designed and targeted for those mutations can be created, and then used in a patient specific manner. The problem is that although you may be able to test for these predictive mutations in other tissues, it is very difficult to obtain tissue samples from various organs. One must also keep in mind that a mutation detected in blood cells is not always present in other organs. The mutations that we are detecting are not always those that one is born with but also those that occur over a person's lifetime due to continual DNA damage and repair. So different cells and organs will have different mutations that occur over time. People are now developing nanotechnologies to take measurements from different cells.