The body constantly makes new cells and removes old or damaged ones. Cancer begins when some cells escape the controls that normally keep that process in balance. They can grow into surrounding tissue and, in some cases, spread to other parts of the body.
But “cancer” is not a single disease. A cancer that starts in the lung is biologically different from one that starts in the breast or blood. Even cancers in the same organ can have different characteristics.
Why those differences matter
The type of cell involved, the changes within it, and how far the disease has spread all shape how a cancer is investigated and treated. A useful test has to answer a specific question in that setting.
That is one reason our work starts disease by disease. Looking for a lung-cancer signal means understanding lung-cancer biology, the people being studied, and the other conditions that may influence a measurement.
A risk factor is not a diagnosis
Age, inherited changes, tobacco exposure, some infections, and environmental exposures can affect cancer risk. Having a risk factor does not mean someone has cancer. Equally, not having a known risk factor does not make cancer impossible.
Symptoms can also overlap with other conditions. Persistent or unexplained changes deserve a conversation with a healthcare professional; an article or an isolated laboratory value cannot determine their cause.
What “looking earlier” involves
Screening looks for signs of disease before symptoms appear in people for whom a screening approach is appropriate. Diagnosis investigates whether disease is actually present. These are related, but different, tasks.
Early-detection research asks which signals are useful, when those signals appear, and what should happen after they are found. The biology is the beginning. The complete pathway matters too.
Sources and further reading
From the BioMarkIQ archive. Edited and updated on 17 October 2026.