Cancer is caused by cells in a particular part of the body that, according to NHS, reproduce in an uncontrolled manner.
These cancer cells can destroy the healthy tissue around them, including organs.
More than a third of all people get cancer at some point in their lives.
You may be exposed to a brain tumor if you have a "severe" headache.
Severe and persistent headaches may be one of the earliest brain tumor alerts, said neurosurgeon consultant Ian Sabin.
He told Express.co.uk that morning headaches are usually worse and gradually improve during the day.
It is not uncommon for the headache to be accompanied by the upright seat, he added.
"Early signs of a common brain tumor can be severe and persistent headaches that persist over a long period of time and are uncommon, ie they are not related to an existing illness," said Sabin, who is also medical director at London's Gamma Knife Center Healthcare UK.
"It is characteristic that they are present in the morning when waking up and often improve when the individual is active.
"Getting up from a sitting position can cause a visual disturbance, with [obscurations] and a sense of powerlessness.
"Sudden headaches, sometimes referred to as thunderbolts, may be due to hemorrhage in and around the brain and need to be investigated urgently.
"Some brain tumors grow faster than others, and it's important to know when to ask a doctor for a second opinion."
You may also be exposed to a brain tumor if you are constantly feeling sick, added Sabin.
Vomiting and nausea are caused by a tumor that disturbs the internal circulation of brain fluid, causing "water in the brain".
While most people feel sick in some places, you should consult a doctor if it is accompanied by a headache or drowsiness.
Other signs of brain cancer include seizures, cognitive changes and even hearing loss.
Every year, more than 9,000 people in the UK are diagnosed with brain tumors.
It can affect people of all ages and they go unnoticed regularly for a long time.
Survival rates vary according to age, type of tumor and location in your brain.
But on average, around 15 percent of all patients live five years after their initial diagnosis, the NHS said.