MYTUTOR SUBJECT ANSWERS

466 views

What causes cancer?

There are lots of different types of cancer which affect different tissues in the body, and two cancers of the same type may not have the same causes. This makes cancer interesting, but also potentially confusing. So it helps to break the issues down to basics.

Firstly, cancer is defined as pathological cellular hyperplasia. ‘Hyperplasia’ means that cells are multiplying, and ‘pathological’ means that this process is causing problems.

Some cell types are constantly multiplying throughout life (like those in skin, hair, bone marrow and the gut wall) but others do not multiply at all (like those in muscle, or nerve cells). This rate of multiplication is carefully controlled by a large number of genes which work together to make sure that a cell only divides when the body needs it to.

Cancers can develop when mutations arise these genes. These may be inherited, happen at random during normal cell division, or have environmental causes like cigarette smoke (‘mutagens’) which make alterations to the DNA molecules of a cell. The effect of these mutations is that cell division is no longer controlled according to the needs of the body as it has evolved, but according to the new, mutated cell.

There are two basic types of genes which are involved in the development of cancers:

 - ‘Oncogenes’ encourage cell multiplication. These contribute to cancerous growth when they are overexpressed, or when they act too efficiently.

 - ‘Tumour suppressor genes’ slow down cell multiplication. These contribute to cancerous growth when they are underexpressed, or do not work properly.

A mutation which makes a cell multiply faster than its neighbours eventually leads to a large collection of similar, rapidly multiplying cells with the same mutation. This is the basis of a tumour.

Because these cells are no longer controlled by the normal system of genes which regulate cell turnover, further mutations in these cells then occur at an increasing rate which help the cancer by improving its blood supply, helping to defend against the immune system, disabling the proteins which correct genetic mistakes and so on. Typically, five or more of these mutations occur before a cancer grows large enough to cause problems.

Mutations also occur which weaken bonds between cells so that they can drift away and start new tumours elsewhere in the body. This is called metastasis and often marks the point at which a cancer becomes incurable.

So really, there is no single cause of cancer but a process involving changes to genes, changes in the behaviour of cells, and changes in the structure of body tissues. Beyond this general picture, understanding the causes of cancer relies on looking at the ways that individual cancers tend to develop.

Frederick H. Uni Admissions Test -Medical School Preparation- tutor, ...

1 year ago

Answered by Frederick, an A Level Biology tutor with MyTutor


Still stuck? Get one-to-one help from a personally interviewed subject specialist

145 SUBJECT SPECIALISTS

£24 /hr

Roslyn I.

Degree: Anthropology with International Relations (Bachelors) - Exeter University

Subjects offered: Biology, Extended Project Qualification+ 2 more

Biology
Extended Project Qualification
English
-Personal Statements-

“My name is Roslyn Irving and I am currently studying for a degree in Anthropology and International Relations. Having taken Science A-levels as well as English I am in a good position to ”

£20 /hr

Lucie C.

Degree: Biomedical Science (Bachelors) - Durham University

Subjects offered: Biology, Maths+ 1 more

Biology
Maths
Chemistry

“Hi! I am a biomedical scientist from Durham University. I am in my second year and I love my subject now more than ever before! Through my tutorials, I aim to inspire you to share this same passion by supporting and aiding your learnin...”

£20 /hr

Jessica E.

Degree: Genetics (Masters) - Leeds University

Subjects offered: Biology, Chemistry

Biology
Chemistry

“Hello! My name is Jess. I am currently in my second year at Leeds University studying Genetics, in which I will go on to do a Masters. I am very enthusiastic about Science as I believe it really is a fascinating subject! I have a pass...”

MyTutor guarantee

About the author

Frederick H.

Currently unavailable: for regular students

Degree: Graduate Entry Medicine (Bachelors) - Oxford, St Hugh's College University

Subjects offered: Biology, .UKCAT.+ 1 more

Biology
.UKCAT.
-Personal Statements-

“I am a graduate of the University of Oxford (Human Sciences), currently training to be a doctor at Bart’s and the London medical school. I was recently asked to help two young friends of my family with their medical school application...”

You may also like...

Posts by Frederick

How does the citric acid cycle work, and what is oxidative phosphorylation?

How much work experience do I need to get into medical school?

How should I prepare for the UKCAT?

What causes cancer?

Other A Level Biology questions

Describe blood supply to the liver?

Explain how type 1 diabetes occurs

Describe the process of translation.

What are the features of alveolar epithelium which allow efficient gas exchange?

View A Level Biology tutors

Cookies:

We use cookies to improve our service. By continuing to use this website, we'll assume that you're OK with this. Dismiss

mtw:mercury1:status:ok