Personalized Medicine - page 4

2) Proteomics

Proteomics looks for patterns among proteins. The term "proteomics" was first coined in 1997 as an analogy with genomics, the study of the genes. The word "proteome" is a blend of "protein" and "genome".

The proteome is the entire complement of proteins, including the modifications made to a particular set of proteins, produced by an organism or system. This will vary with time and distinct requirements, or stresses that a cell or organism undergoes.

While genes are the 'recipes' of the cell, containing all of the instructions for assembly, proteins are the products of these recipes, functioning as the cellular "engines" that drive both normal and disease physiology.

"So while genomics may provide the likelihood of developing a certain disease, proteins may diagnose what is happening in a patient in real time. Together, these complementary fields (genomics and proteomics) are absolutely necessary for understanding the molecular underpinnings of disease and for enabling personalized medicine." Quote from National Cancer Institute

Image Courtesy of U.S. Human Genome Project

However, proteomics is much more complicated than genomics. This is because while an organism's genome is more or less constant, the proteome differs from cell to cell and from minute to minute depending on the activity of specific genes. This makes interpreting a protein measurement difficult.

Whereas genomic studies of cancer usually require tumor tissue, proteomic studies mostly look at proteins circulating throughout the body. So these studies can be conducted using blood, urine or other body fluid samples.

• Tumor Biomarkers

A breakthrough in cancer treatment was the discovery that tumors "leak" proteins and other molecules into blood, urine, and other accessible bodily fluids.

This insight has led to the possibility of diagnosing cancer at an early stage simply by collecting such fluids from patients and testing them for the presence of cancer-related molecules, also called "cancer biomarkers/tumor markers". The greatest promise for the early detection and treatment of cancer lies in the ability to find valid molecular indicators, or biomarkers, of the disease.

• Problems in Using Proteomics

Although protein biomarkers hold great promise in our fight against cancer, there are significant challenges that must be overcome:

• Lack of standardization - Today, laboratories across the country collect, store, and study proteins in different ways. This lack of standardization makes it difficult to accurately compare results from one laboratory to another and limits the number of cancer protein or biomarker tests that are available to the public.
• The huge numbers of proteins that exist in the body make it difficult to identify and characterize.
• Proteins are continually moving and undergoing changes. All of these actions and/or interactions need to be better understood.
• Proteins exist in a wide range of concentrations in the body. The most important proteins for understanding and/or detecting cancer may be those found in the smallest concentrations, which means being able to detect them is a major problem.
• Most tests today have problems with false positives and false negatives.
• Possible Solutions to Problems in Proteomics
  • Scientists have proposed that in order to develop more sensitive and specific cancer diagnostic tests, many biomarkers should be measured simultaneously.

		It is thought that patterns revealed in a panel of biomarker proteins associated with a form of cancer - known as a "protein signature" - might have better diagnostic and predictive capabilities than the current single-marker approach.
Image courtesy of Purdue University, Dr. W. Andy Tao

• Standardize collection and testing of samples

Summary:

Diseases such as cancer, while based on genomic mutations, show up as problems in protein signaling. Pharmaceutical interventions aim to fix the faulty protein activity, not the genetic defect.

3) Metabalomics

Metabolomics is the systematic study of the unique chemical fingerprints that specific cellular processes leave behind. More specifically, it is the study of metabolic responses to drugs, environmental changes and diseases.

Metabolomics is an extension of genomics (concerned with DNA) and proteomics (concerned with proteins). Following on the heels of genomics and proteomics, metabolomics may lead to more efficient drug discovery and individualized patient treatment with drugs, among other things.

		Not all metabolites can be found in any given tissue or biofluid. Most often the biological samples used to measure metabolites are urine, saliva, and blood plasma. While genomic data and proteomic analyses do not tell the whole story of what might be happening in a cell, metabolic profiling can give an instantaneous snapshot of the physiology of that cell. This may be very helpful in all areas of disease detection and treatment.
Image courtesy of Royston Goodacre School of Chemistry, The University of Manchester