1 - The biological basis of cancer and the problem of drug resistance

Summary

Introduction

The phenomenon of resistance to environmental toxins has probably been present ever since life first evolved on earth. Any early living organism that happened to produce chemicals that were toxic to its competitors would have had a significant survival advantage in the struggle for existence. Competing species that failed to evolve a satisfactory protective mechanism against these toxins would have become extinct, but those that were able to circumvent successfully the toxins produced by other organisms would have been able to survive. Over the billions of years that life has evolved, organisms have developed an immense variety of chemical weapons against competitors and predators, who have in turn evolved mechanisms to permit their own survival.

The development of antibiotics and other chemical compounds for the treatment of infectious disease has been one of the triumphs of 20th century medicine. However, it is not clear at this point whether the gains made against many pathogenic organisms can be maintained. Strains of disease-producing bacteria that are resistant to most or even all of the available therapeutic agents are being increasingly encountered. The lay press is filled with stories about ‘super bugs’ that have ‘learned’ to overcome antibiotics. These popular accounts somehow manage to convey the picture of bacteria sitting down around a conference table and consciously planning their battle strategy against human beings. As if dealing with pathogenic microorganisms was not enough, the human race also has to contend with the evolution of its own aberrant cells, in the form of cancer, becoming resistant to the agents that are available for systemic treatment.

The underlying theme of this book is that there is a common thread to all of these problems.