Liberman describes a number of experiments done with full spectrum light and /or specifically selected colors. Studies done on mice that were bred to develop tumors, indicated that a pink light environment resulted in the earliest development of tumors while full spectrum light inhibited the development of tumors for a twenty percent longer period of time. Older cells are more at risk for accumulated DNA damage that precedes cancer. Experiments done on fish and paramecia using near-ultraviolet radiation indicated that the damaged cells not only repaired themselves but also reversed their aging. What if it is discovered that human cells have the same capabilities?
Since 1900 when scientists first noted that certain substances were damaging to living tissue when exposed to light, but were not toxic in the dark, it has been discovered that many of these substances belong to a family of light-activated chemicals called porphyrins produced by almost all living organisms and necessary for cell respiration.
During World War II (1942) it was noted that if porphyrins were present in one's body, tumors would floresce under light, brilliant red under ultraviolet light. This discovery was built upon in 1973 when technology made photodynamic therapy
possible. Scientists found that certain photosensitive chemicals selectively identify cancer cells under ultraviolet light and accumulate in these cells. Then, under red light, these chemicals destroy the cancer cells. 1
As of the 1991 publication date of Light-Medicine of the Future, only Photofrin (DHE) had been FDA approved for human use. After injection with a prescribed amount of Photofrin, the patient has to wait for up to seventy-two hours in an environment free of direct sunlight or other bright lights so that some of the Photofrin which also collects in certain normal tissues (kidneys, liver, spleen, and pancreas) can be eliminated. The treatment is delivered to the site of the tumor by hair thin fiber optic tubes. The result is that within hours the cancer cells begin to die leaving most normal tissues unharmed. "Even in tissues that are just partially cancerous, only the cancerous portions of the tissue will die. Since the specific photosensitive dyes are combined with highly tuned Laser light, the treatment is extremely precise." (113)
On February 26, 2008 I did an on line search on Photofrin (DHE) through Encarta Encyclopedia to ascertain any further clinical trials/developments utilizing Photofrin. According to the National Cancer Institute (NCI) Drug Dictionary, Photofrin is still the U.S. brand name and (DHE) the abbreviation. Synonyms are: dihematoporphyrin ether, Photofrin II, and Porfimer. The name Photofrin II indicates some new version of the original Photofrin.
The National Cancer Institute, as of February 26, 2008, lists two closed published clinical trials (1/1/2000, and 10/2/2003), three active published trials (3/22/2007, 9/12/2007, and 1/24/2008), one active non-published trial and two approved but not yet active trials. All deal with Photodynamic Therapy using one or another of the brand names (synonyms) for photofrin. The studies deal with an array of cancers: Bilary Tract Tumors, Cholongiocarcinomas, Bladder, Upper Digestive Tract, Esophageal, Lung and Squamous Cell Carcinoma of the Larynx.
It certainly appears that Light based therapies and medications are the Medicine of the Present and Future!

Endnote:

1 Jacob Liberman, Light-Medicine of the Future (Santa Fe, New Mexico: Bear and Company.1991) pp. 111-112. This and subsequent direct references from this work are reprinted by permission of Inner Traditions International, Rochester, Vermont.