We all remember the promise of stem-cell technology when scientists at the University of Wisconsin and Johns Hopkins University first isolated and successfully cultured human pluripotent stem cells back in 1998 - that these miracle cells would lead to products that would revolutionize medicine.

Now it's thirteen years later and the collective interest in stem cells has waned, but that doesn't mean scientists aren't still plugging away trying to realize the dream that once was. Before we get to recent advancements in stem-cell technology and why we think investors will soon show renewed interest in it, let's take a step back and review what makes stem cells special, and how they could impact medicine.

Stems cells differ from other cell types due to three main characteristics that all stem cells share, regardless of their source:

1. They are capable of dividing and renewing themselves for long periods;

2. They are unspecialized; and

3. They can give rise to specialized cell types.

Because of stem cells' potential to develop into many different cell types and their unique ability to serve as a sort of internal repair system, dividing essentially without limit to replenish other cells, their potential implications for medicine are profound.

Studies of human embryonic stem cells (hESCs) could provide valuable information about the complex events that occur during human development. By identifying how undifferentiated stem cells become the differentiated cells that form our tissues and organs and developing a more complete understanding of the genetic and molecular controls of these processes, scientists may be able to develop new ways to treat various birth defects and cancer, which are the result of abnormal cell division and differentiation.

Stem cells could also be used to test new drugs. New medications could be tested for safety on differentiated cells created from human pluripotent stem cell lines, allowing for drug testing in a wider range of cell types.

And then there's the holy grail of stem-cell research: the generation of cells and tissues for use in cell-based therapies. It's no secret that the need for transplantable organs and tissues far outweighs the available supply. With the potential to develop into specialized cells, stem cells could be used as replacement cells and tissues to treat countless conditions, including heart disease, diabetes, spinal cord injury, and arthritis.

For example, take diabetes. In people with Type I diabetes, the cells of the pancreas responsible for producing insulin are actually destroyed by their own immune system. Studies have shown that it may be possible to direct the differentiation of hESCs in cell culture to form insulin-producing cells that eventually could be used in transplantation therapy.

But what about the ethical issues involved in stem-cell research?

Thanks to advancements in technology, the research is becoming less controversial.

During the early days of human stem cell research, scientists worked with two kinds of cells: embryonic stem cells and non-embryonic "somatic" or "adult" stem cells. Each of these types of stem cells has advantages and disadvantages regarding potential use for cell-based regenerative therapies, but embryonic stem cells are usually more highly prized because they are pluripotent and have the potential to differentiate into almost any cell in the body. Adult stem cells are thought to be limited to differentiating into different cell types of their tissue of origin.

What's more, large numbers of cells are needed for stem-cell replacement therapies, and while embryonic stem cells can be grown relatively easily in culture, numerous challenges remain when it comes to isolating adult stem cells from the tissue and expanding their numbers in cell culture.

But in 2006, scientists came up with a solution that would allow research on pluripotent stem cells while bypassing the ethical issues associated with the production of hESCs. Researchers working at Kyoto University in Japan identified conditions that would allow specialized adult cells to be genetically "reprogrammed" to assume a stem-cell-like state.

To quote Dr. Charles A Goldthwaite's article, The Promise of Induced Pluripotent Stem Cells (iPSCs):

These adult cells, called induced pluripotent stem cells (iPSCs), were reprogrammed to an embryonic stem cell-like state by introducing genes important for maintaining the essential properties of embryonic stem cells (ESCs). Since this initial discovery, researchers have rapidly improved the techniques to generate iPSCs, creating a powerful new way to "de-differentiate" cells whose developmental fates had been previously assumed to be determined.

Although much additional research is needed, investigators are beginning to focus on the potential utility of iPSCs as a tool for drug development, modeling of disease, and transplantation medicine. The idea that a patient's tissues could provide him/her a copious, immune-matched supply of pluripotent cells has captured the imagination of researchers and clinicians worldwide. Furthermore, ethical issues associated with the production of ESCs do not apply to iPSCs, which offer a non-controversial strategy to generate patient-specific stem cell lines.

While numerous technical hurdles remain - and it's unclear whether iPSCs could ever fully replace hESCs in the lab - the technology represents a big step forward in stem-cell research.

Some other recent advancements that could stoke investor interest include:

• In January 2011, researchers at Tottori University in Japan successfully made heart pacemaker cells using the embryonic stem cells of mice. The achievement could lead to breakthroughs in the treatment of arrhythmia and could reduce the need for electronic pacemakers in human patients.

• In November 2010, the FDA approved a trial to test an embryonic stem-cell-derived therapy in the treatment of an inherited disease that causes blindness in young people.

• In October 2010, 12 years after human embryonic stem cells were first isolated, a therapy derived from such cells was tested in humans for the first time.

• In August 2010, according to an article from the Daily Telegraph, scientists created synthetic blood using hESCs, which could aid victims of large-scale disasters when blood bank supplies are low. The scientists, who are working with the Wellcome Trust in Great Britain, say their ultimate goal is to create the rare O negative blood type. It can be given to any patient without fear of rejection, but is produced by only 7% of the population.

• In January 2010, researchers at Stanford showed that transplanted neurons grown from embryonic stem cells were able to form proper brain connections in newborn mice. The discovery, which demonstrates that stem cells can be directed to become specific brain cells, could lead to new treatments for nervous system diseases like ALS (Lou Gehrig's disease) as well as for spinal cord injuries.

The point is that advances in stem-cell research are being made every day. The technology has finally reached the stage of human trials. And while years of intensive research are still necessary to overcome the technical hurdles that remain, there's little doubt that fortunes will be made by prudent early investors in the space.

Stem cells are just one of many biotech advances that may revolutionize treating many diseases in the very near future. The Casey Extraordinary Technology team has put together a "curing cancer" portfolio that includes other advances that could also revolutionize your investments. Don't let this opportunity slip by!