Sometimes people experiences changes in the shape of their fingers and nails.
This can include curving nails, the nail bed softening, the skin next to the nail bed becoming shiny and the ends of the fingers getting larger.
These changes are known as finger clubbing and can often be an early warning sign of lung cancer.
According to Cancer Research, more than 35 percent of people with non-small cell lung cancer experience finger clubbing.
Also known as the 'diamond gap' test, it involves pressing your nails together and checking whether there's a tiny diamond-shaped window of light between them.
If you don't have the 'diamond gap' then it's possible you could have finger clubbing.
Those who think they might have finger clubbing are advised to speak to their doctor.
In a post on their website Cancer Research says: "Finger clubbing is unusual. If you have it and are worried, do speak to your doctor.
"They should send you for a chest x-ray to check your heart and lungs."
They added: "Clubbing is thought to be caused by fluid collecting in the soft tissues at the end of the fingers.
"This is caused by more blood flowing to the area than usual. But we don't fully understand why this happens.
"It may be due to the tumour producing particular chemicals or hormones."