**4. Conclusion**

Technology has finally caught up with science fiction. The idea of a pin prick to divine ones' future is fast becoming a reality. Science is moving medicine in a direction where patient care will be predicted and prevented, and not watched from afar. Data-rich and highly sensitive techniques like microarray profiling, quantitative PCR, and Next Generation Sequencing are the genomics tools that are helping to drive these changes. However, to extract the greatest utility, tests need to be simple to complete, cost effective and as noninvasive as possible. Clinical impact is directly related to the availability and cost of a test. Consider the case of standard tumor biopsy. Depending on the disease and tumor location, a biopsy can be minor surgery involving a team of doctors, nurses, radiologists, and specialists. Recovery from a biopsy is often brief, but in some cases can lead to a costly overnight hospital stay. In the end, the actual cost of obtaining material for a test can be in the thousands of dollars, while the test itself, may only be a couple of hundred of dollars. For many biomarkers, there is more cost associated with the acquisition of sample, than the test itself. It is for this reason it makes both clinical and financial sense to find ways to make sample acquisition more cost effective and less precarious for the patient.

By studying often overlooked sample types, we may identify a treasure trove of clinically useful biomarkers. While not every surrogate tissue will yield a disease or response-specific biomarker, there is substantial data to justify the investigation. There is undeniable value in the use of biomarkers in drug development and patient care, but this value is tempered with the cost of sample acquisition. Developing methods for the acquisition of clinically useful and easily obtainable samples is important as we move from a drug discovery process that is focused on finding the right drugs to one that focuses on finding the right patients.
