Molecular Diagnosis, Targeted Therapy: Cancer as a Case in Point
One important insight derived from molecular research is that cancer is not just cancer. The term covers some 250 different conditions, almost all of which affect body tissues. While these conditions display major differences in their symptoms and delayed effects, there is one thing that breast, lung, intestinal or skin cancer all have in common: they are ultimately genetic diseases.
Some genetic defects triggering cancer are inherited; others are acquired in the course of our lives as a result of factors that encourage cancer like tobacco smoke, radiation or viruses. Additionally, life-style and psychological factors can contribute to the development of cancer. All these ‘carcinogens’ function in the same way: they damage the ‘life molecule’ DNA.
Many such defects or damage will never impair the functioning of our genetic systems, not least because the cell has ‘repair services’ at its disposal that can quickly remedy irregularities like a DNA letter in the wrong place. But if there are alterations to genes that are particularly vital for the life of the cell, if the defects cannot be repaired or compensated for, or if a large number of genetic defects accumulate in the course of time, then cancer may be the result.
Such lasting changes interfere with important cellular mechanisms that normally regulate and control how cells proliferate. Cellular growth goes awry and uncontrolled cell division is the upshot. The rogue cells oust and damage healthy tissue. Things become even more serious when these degenerate cells find their way into the circulation or the lymph system and ultimately establish themselves elsewhere in the body as secondary tumours, also known as metastases.