Before we consider cancer, we need to take a look at tumours, as the most common misconception made by both students and adults is to think that these two terms mean the same thing. Now, a tumour is an abnormal mass of cells that forms when a group of cells undergo uncontrolled growth and division. Importantly though, there are two different types of tumours, benign and malignant, and it's only the malignant ones that are considered to be cancer.
In a benign tumour, the abnormal group of cells are contained within one area, usually within a membrane, and because they stay in that one place, they're not normally dangerous, so we don't call them cancer. Malignant tumours on the other hand, don't stay in one place. They're able to invade other tissues and spread to different parts of the body, where they can form new secondary tumours. This process can cause a lot of damage to our body, making malignant tumours far more dangerous.
potentially fatal, which is why we classify them as cancer. So now that we know what cancer is, we can consider the risk factors that increase the chance of us developing it. One strong link that you probably already know about is between smoking and lung cancer, but smoking has also been linked to a range of other cancers too, like mouth, stomach and cervical cancer. Obesity has also been linked to multiple cancers, including bowel, liver and kidney cancer. Meanwhile, ultraviolet light exposure, which we get from both the sun and from sunbeds, is strongly linked to skin cancer, because the UV radiation can damage our skin cells.
And just like obesity, drinking alcohol is also linked to an increased risk of liver cancer. Risk factors aren't always lifestyle choices though. Sometimes it's the genes that we inherit from our parents that make us more susceptible to certain cancers.
For example, the BRCA genes are linked to developing breast and ovarian cancer. Anyway, that's all for now. If you found this video useful, then give us a like and we'll see you next time.