Finally! A Molecular Approach to Cancer Therapy

From my earliest days as a wet-behind-the-ears medical student, I have been dismayed at the labyrinthine treatment rules to the treatment of various cancers, depending on the site of origin. Oncology almost seemed like a glorified form of voodoo medicine. Now, with the arrival of better tools of cell and molecular biology being utilised in hospital labs, it is finally becoming possible to treat cancers rationally, based upon the actual molecular behaviour of the tumour itself.

This newsrelease from the Washington University School of Medicine in St. Louis, Missouri, provides more information into this better approach to oncology.

The researchers found that, independent of anatomical origin, some tumors had high amounts of irinotecan's cellular target, a protein labeled TOP1, while other tumors had very little. Irinotecan would likely be ineffective in tumors with low TOP1 levels. They also found that tumors varied greatly in the amounts of proteins that transport irinotecan into and out of their cells and in the amounts of proteins that break down irinotecan. These variations determine how well irinotecan will work in a particular tumor.

"Because tumor response can't be predicted from anatomical location, we should start selecting treatments based on what genes and proteins can tell us about how the tumor will respond to a drug," says McLeod, professor of medicine, of genetics, and of molecular biology and pharmacology. "If we rely just on what has clinically been shown to work in some cases for a particular anatomically defined cancer, we may not initially choose the best therapy for the individual patient. And with advanced cancer, a patient may get only one shot at the right therapy — making the wrong choice could be deadly."

According to McLeod, under current treatment selection methods virtually no chemotherapeutic drug has been successful in more than 50 percent of patients with advanced cancer. But instead of considering a drug that works only ten percent of the time a failure, he feels it would be better to consider such a drug effective for one in ten tumors and to search for the agents among the current arsenal of chemotherapeutic drugs that will work for the rest.

"We have more than 70 FDA-approved drugs that potentially could be useful for a particular tumor," McLeod says. "We are now working on methods that can be used to identify those drugs that will work for each patient's tumor." Source.

Besides radically changing current oncology therapies, the new biological tools will also bring more effective drugs to the regulatory process more quickly. Treating cancer is beginning to seem a lot less like Voodoo Medicine, than it once did.