Hi, there.

I'm Mrs Kemp.

And welcome to today's lesson.

This is all about cancer, and it fits into the unit of Health and Disease.

So, let's get started then.

Our main outcome for today is "I can explain how a cancerous tumour is formed "and identify some risk factors "that increase the likelihood "of a person developing cancer." These are some of the key terms that we're going to be using today, and if you would like to pause the video and have a look at them in more detail, then you can.

Otherwise, rest assured that I will go through each one of these as we move through the slide deck.

So we've got three learning cycles for today: cancer, risk factors for cancer, and also HPV and cervical cancer.

Of course, we'll start by explaining actually what cancer is.

So it's actually a non-communicable disease and that's because it cannot be passed from organism to organism.

And there are lots of different places on the body where you can get cancer.

The four most common types that we find here in the UK are breast cancer, lung cancer, prostate cancer, and bowel cancer.

So even there we've got quite a big range, haven't we, across the whole body.

Now, in order to understand cancer, we need to know a little bit about cell division, okay? So cell division happens as a normal part of your growth and also replenishing cells and tissues.

This happens by a process of cell division known as mitosis.

And you can see that we've got a starting cell, and, by the end of the process of cell division, we've got two new cells at the end.

Now, sometimes there can be a mutation, so a change in a gene that actually controls this process of cell division.

When that happens, that cell could start dividing uncontrollably, okay? So once we've got those two new cells, they then divide into two new cells, and they then divide into two new cells much faster and out of control as they would do normally.

This is what we call a tumour.

Okay, let's do our first check, then.

Two students were discussing cancer.

Who has the best description of a tumour? Aisha, "A tumour is a mass of cells "that has been produced through uncontrolled cell division." Izzy, "A tumour is a type of specialised cell." I'll give you a moment to think about it, but if you need more time, please pause the video.

Okay, did you realise that it was Aisha? "A tumour is a mass of cells "that has been produced through uncontrolled cell division." Excellent.

Well done.

So, actually, not all tumours are cancerous, all right? There are two different types, and we categorise those into benign and malignant.

So let's have a look at those in a little bit more detail.

This one over here on the left, this one is a benign tumour, okay? And it is not cancerous.

Our malignant tumour, then, on the other side, is cancerous, and we can see, just by looking at those images, that there is a difference between the two.

One is sort of contained, isn't it? While the other one is breaking out into the tissue around it.

So, the benign tumours then, the ones that are not cancerous, all right, they are growths of abnormal cells, and they are contained within an area.

They usually grow quite slowly, so much more slowly than you would expect cancer to.

They're contained within a membrane, and you can see that membrane that is formed around that little cluster of cells, okay? And that prevents it from actually invading any of the neighbouring tissue around it.

Let's have a look at malignant then.

Malignant are cancerous tumours, and they're actually not contained within that area.

They don't have that membrane surrounding the cluster of cells, and so, what happens to them is they're actually able to break out and invade other tissues around them.

They're also able to break off from the top, okay? And so then they're actually able to spread around in the blood and take up a place elsewhere in the body.

This is known as metastasis.

So let's have a look at those side by side.

We've got benign tumours that are non-cancerous.

They're encapsulated, so they're surrounded by a membrane.

They're non-invasive to other organs and tissues around them.

Malignant tumours then.

These are cancerous ones.

They're less likely to be encapsulated, so they're not inside that membrane.

Therefore, they are able to break off and travel around in the blood causing potentially secondary tumours elsewhere.

They're usually more harmful than the benign tumours.

The benign tumours only really cause major problems when they're actually in the brain.

Otherwise, in other parts of the body, then they're not as bad.

So a true or false check for us then.

Benign tumours are more dangerous than malignant tumours.

True or false? Justify your answer.

Benign tumours do not invade other organs or tissues.

Malignant tumours can break off and travel in the blood to form secondary tumours.

I'll give you a moment to think about it, but if you need more time, please pause the video.

Okay? Did you realise that that was actually false? And that's because benign tumours are not able to invade other organs or tissues.

It's actually malignant tumours that are cancerous.

Alright, onto our first task of the day then.

So if you get your worksheet out, you can record this into task A.

What I would like you to do is sort these statements into either benign or malignant tumours.

So you've got non-invasive to other organs and tissues; cancerous; non-cancerous; less likely to be encapsulated; capable of breaking off and travelling through the blood to cause secondary tumours; and encapsulated, surrounded by a membrane; usually more harmful.

I'll give you a moment to think about it, but if you need more time, please pause the video.

Okay, let's have a little look at how we should have separated those then.

For benign tumours then, we've got non-cancerous, encapsulated, non-invasive to other organs and tissues, and then we've got, for our malignant, they are cancerous, less likely to be encapsulated, capable of breaking off and travelling through the blood to cause secondary tumours as metastasis, usually more harmful.

Okay, hopefully you sorted those correctly.

Otherwise, maybe you could draw a little arrow to show that you need to move it into the other area.

Alright, onto our second learning cycle of the day.

Risk factors for cancer.

So there are actually more than 200 different types of cancer.

So there are a lot of them, and, actually, even though they're in different parts of the body, they actually share quite similar risk factors.

Remember, a risk factor is something that's going to increase your chance of developing a disease.

So, for example, smoking.

Smoking contains tar.

Tar is a carcinogen, so when we breathe it into our lungs, then it's more likely to cause lung cancer there.

We've also got other types of carcinogen such as asbestos.

This is a material that they often used in insulation.

We don't put it in insulation anymore because it's realised that actually if we breathe that into our lungs, it's much more likely to cause lung cancer as well.

Exposure to certain types of radiation including UV light.

Okay, remember UV light can be linked with skin cancer especially.

Being overweight or obese.

If you are in those categories, you are more likely to develop types of cancer.

And then there are also genetic factors, where if somebody in your family has got a certain type of cancer, actually you are more likely to also get that.

So the tar in the cigarette smoke is the thing that causes the cancer.

So, when we breathe it in, anywhere that tar can collect actually is more likely to cause a mutation in the DNA of the cells that are there because it's damaging that DNA, and this can then lead to uncontrolled cell division.

And, remember, uncontrolled cell division could lead to a tumour which may be malignant, okay? If it's malignant, then it is cancer.

We can see in that image that we've got places in the mouth, in the trachea, and also in the lungs where that could take place.

UV light then, ultraviolet radiation from the sun or also if you are having a lot of sun beds, for example.

That's what we can see in the image there.

That can also have the same effect on DNA because it can damage the DNA.

Now, actually, UV light can actually penetrate into the skin cells and break apart that DNA.

When that happens, it could lead to a mutation.

That mutation could lead to uncontrolled cell division which, again, would cause a tumour, and that tumour could potentially be malignant, and, if it is, that's what we call cancer.

Being overweight then or obese is also a major risk factor for many types of cancer, and, actually, it can be listed as one of the major risk factors.

There are several reasons why the link has been made between overweight and cancer.

One of them is actually the fat cells themself actually produce a hormone known as oestrogen.

Now, you may have heard of oestrogen before because it's also the female sex hormone.

So it actually does lots of important things in our body, but, unfortunately, what that hormone can do is it can actually promote the growth of certain types of cells including cells that are cancer cells, and, in particular, breast cancer cells can be triggered to grow by oestrogen.

So the more fat cells you have, the more likely these cells are going to grow.

Okay, which of the following are risk factors for cancer? We've got a, being overweight; b, eating a healthy diet; c, exercising regularly; or d, smoking.

I'll give you a moment to think about it, but if you need more time, please pause the video.

Okay, being overweight and also smoking.

That's a and d.

Hopefully you got those right.

Well done.

Okay, so to lower our risk of getting cancer, we should try, for example, to eat a more balanced diet, okay? So reducing our consumption of ultra processed foods because they are likely to be high in fat and sugar and could lead us to become overweight.

When we reduce those then, what can we do in exchange? Well, we should increase our consumption of fruits and vegetables and whole foods, okay? This is going to make sure that we're able to keep a healthy weight.

Exercising regularly can also help to maintain a healthy body weight, and is much more sustainable.

So you're much more likely to be able to do that if you choose a sport or an activity that you actually enjoy.

So are you meeting up with friends to do it? Is it fun? Are you enjoying it, okay? These are the types of things that are more likely to help you to continue exercising.

Do make sure that you don't smoke or take illegal drugs and also avoid drinking alcohol, okay? Excessive alcohol can also lead to types of cancer.

So which of the following can reduce your risk of developing cancer? a, avoid alcohol; b, eating a healthy diet; c, being overweight; or d, smoking.

I'll give you a moment to think about it, but if you need more time, please pause the video.

Okay? Did you get avoid alcohol? Excellent.

Well done.

And also eating a healthy diet.

Brilliant.

So, some people, as well as the other lifestyle factors that we have, some people also have an increased risk of a particular type of cancer because they've actually inherited a faulty gene from their parents.

It is important to note that actually most cancers are not caused by an inherited faulty gene.

So actually most things are due to lifestyle factors.

So there are two different types of gene, BRCA1 and BRCA2.

You don't need to know the names of those, so don't worry.

Actually, these are genes that help to control cell division.

Changes in these genes can lead to an increased risk of developing cancer and that's because we've got those types of genes when they have mutated, then actually they can lead to that uncontrolled growth leading to a tumour and then potentially cancer.

Changes to the genes can then be passed from parent to offspring because obviously we get their DNA from the egg and the sperm that made us, okay? So, therefore, they can pass that, and we can inherit it.

This means that the offspring would then have a greater chance of actually developing those particular types of cancer.

Often we see this in examples such as breast cancer.

You can get a genetic test to see whether or not you have inherited those genes.

Okay, onto our next task of the day then.

This one is task B, and so you can record this on your worksheet.

Describe how eating an unbalanced diet and not exercising regularly can lead to an increased risk of breast cancer.

I'll give you a moment to think about it, but if you need more time, please pause the video.

Okay.

Did you think of all of these things? Eating an unbalanced diet and not exercising may lead to a person becoming overweight or obese.

Fat cells produce the hormone oestrogen.

Excess oestrogen can promote the growth of cells leading to faster uncontrolled cell division.

This mass of cells that is dividing uncontrollably is a tumour.

The tumour may be benign or malignant.

A malignant tumour is cancerous.

Hopefully you've got all those points down, but, if not, please pause the video and add a couple in.

On to our final learning cycle of the day then.

This is HPV and cervical cancer.

So HPV stands for the human papilloma virus.

It's actually the name of a group of different viruses.

They're often harmless in people, and we don't even know that we've got them, but, in some people, it can cause genital warts.

Now, the reason that we don't know that we've got them is actually they are symptomless.

So we don't know that we have them, and then we can pass them on to other people unknowingly.

It is actually passed through sexual activity, and so, therefore, it is a sexually transmitted infection.

When the virus has been passed then, and it gets into a host, what it does is it actually enters the host cell.

We can see a virus there entering a host cell, and it changes the host cell's genes, and we know that if genes are being changed, and they're the ones that are being controlling cell division, then actually that could lead to the cell dividing uncontrollably, and this can potentially lead to a tumour and then potentially be malignant and be a cancerous cell.

There are ways to reduce the spread of HPV then.

Because it is a sexually transmitted disease, any kind of barrier method for contraception will help to slow down the spread of the virus.

In particular, we can see in the image there, a condom, but unfortunately they don't actually cover the skin around the genitals, and therefore you're not completely protected from the warts, for example, actually where you've got skin on skin.

What is happening at the moment is the HPV vaccination of lots of people, young people being vaccinated against HPV, and this is going to be the most successful way in order to control the spread, okay? It only protects you against the HPV types that actually cause warts and cancer, so it doesn't protect you against all types of HPV.

In Australia, if we look to Australia, actually, they've had a really successful vaccination programme, and the numbers and cases of cervical cancer have dramatically reduced, and, in the future, it's hoped that actually they will no longer need screening against cervical cancer because the numbers are so low.

Okay, which of the following are associated with HPV? a, cancer; b, diabetes; c, obesity; and d, genital warts.

I'll give you a moment to think about it, but if you need more time, please pause the video.

Okay.

Did you go for a, cancer and d, genital warts? Excellent.

Well done.

Okay, onto our next check.

How can we protect ourselves against HPV infection? a, using condoms; b, cook food properly; c, vaccination; and d, wash hands.

I'll give you a moment to think about it, but if you need more time, please pause the video.

Okay, of course, it's condoms and vaccination.

Excellent.

Well done.

Now, let's have a little look at this data together about some of the different strains of HPV.

So I said there are different types of them, and we can see along the x-axis there that we've got HPV 6, HPV 11, HPV 16, and HPV 18, and finally HPV 33.

On the y-axis, we've got the percentage cervical cancer tumours containing HPV.

So, actually, what we can see is that HPV 6 and 11 do not appear to be found in any of the cervical cancer cases, okay? So it's probably that these ones are not having an effect.

They're not a risk factor for cervical cancer.

16, 18, and 33 have all been found in some different cancer tumours, okay? So these could be a cause for the cancer.

However, on graphs such as this, without any other information, really we could say that correlation doesn't always mean causation.

So, yes, there is a correlation.

We can see that 16 is found in nearly 60% of all cervical cancer cases, but we don't know that it definitely is the cause just from this piece of information.

So when we're looking at data, remember, we do also have to think about where it's come from and how it's been made in order to decide whether or not it is actually causing that disease.

Onto our next check then.

True or false? HPV is a bacterium.

Is that true, or is that false? a, HPV stands for human papilloma virus; or b, HPV causes damage to the cells.

I'll give you a moment to think about it, but if you need more time, please pause the video.

Okay, did you realise that that's false, and that's because actually HPV stands for human papilloma virus, all right? So it's definitely a virus and not a bacterium.

So onto our last task of the day, and we're going to look at this bar chart again that we saw earlier on, and you can record this on your worksheets.

So use the bar chart to evaluate the claim HPV causes cervical cancer.

Include some reasons that agree with the claim and some that disagree with the claim.

Then write a conclusion.

I'll give you a moment to think about it, but if you need more time, please pause the video.

Okay, so HPV strains 16, 18, and 33 have all been associated with cases of cervical cancer.

HPV 16 has been found in nearly 60% of cervical cancer patients which is more than the other strains.

HPV 6 and 11 have not been found in any cervical cancer patients.

I believe this suggests that only some strains of HPV are associated with cervical cancer, but correlation doesn't always mean causation so we cannot make the claim that HPV causes cancer based on this evidence.

If you need to add some more into your answer, please do that now.

Okay, so onto our final summary for today then, and we're going to move through the key learning points with you.

Cancer is a non-communicable disease and cannot be passed from organism to organism.

A tumour is a mass of cells that has been produced through uncontrolled cell division.

Tumours can be benign or malignant.

Benign tumours are non-cancerous and less harmful.

Malignant tumours are cancerous and more harmful because they can break off and spread to other parts of the body.

There are risk factors associated with cancer such as smoking or certain genes.

HPV can be sexually transmitted infection that is passed on through sexual contact that can increase your risk of cervical cancer.

I've really enjoyed today's lesson.

I hope you have too.

Thank you so much for learning with me.

Goodbye.