THE CANCER/MITOSIS THE CANCER/MITOSIS CONNECTIONCONNECTION

A cance

r cell

Ted Ed

How do cancer cells How do cancer cells behave differently behave differently from healthy cells?from healthy cells?

All cells have a All cells have a controlled rate of controlled rate of divisiondivision that is that is appropriate for their appropriate for their role in the body.role in the body.

Cancer/MitosisCancer/Mitosis

Rates of DivisionRates of Division

E.g. The cells E.g. The cells of the of the skinskin reproduces reproduces perfectly so perfectly so that it does that it does not become not become too thin or too too thin or too thickthick

Rates of DivisionRates of Division

E.g. Cells that line the E.g. Cells that line the intestineintestine complete the cell complete the cell cycle in cycle in 24-2824-28 hours hours

Rates of DivisionRates of Division

E.g. E.g. LiverLiver cells cells reproduce reproduce only once a only once a yearyear

Rates of DivisionRates of Division

E.g. E.g. NerveNerve cells never reproducecells never reproduce

Rates of DivisionRates of Division

E.g. E.g. Frog embryo cellsFrog embryo cells reproduce in less than an hourreproduce in less than an hour

Rates of DivisionRates of Division

Cells spend most of their time in Cells spend most of their time in interphaseinterphase. .

The The mechanism for cell mechanism for cell growth is highly regulated by growth is highly regulated by genesgenes (segments of DNA) in the (segments of DNA) in the cell so that you just get the new cell so that you just get the new cells you need.cells you need.

Rates of DivisionRates of Division

If the control If the control mechanism for mechanism for this process this process gets messed up, gets messed up, the rate of the rate of mitosis in that mitosis in that body tissuebody tissue increasesincreases

Cancer cell division. Colored scanning electron

micrograph (SEM) of two prostate cancer cells in the final stage of cell division

(cytokinesis).

Increased Mitosis…leads Increased Mitosis…leads to…to…

Accumulation of cellsAccumulation of cells in in that area known as a that area known as a tumortumor

Kidney tumors

Increased Mitosis…leads Increased Mitosis…leads to…to…

CANCERCANCER – A disorder of cells in which the A disorder of cells in which the

genes which control growth genes which control growth have been have been damaged and the damaged and the cells have the ability to cells have the ability to spread throughout the body.spread throughout the body.

Ovary Cancer Cell

Causes of cancer:Causes of cancer:

VirusesViruses Chemicals (such Chemicals (such

as Nicotine**, as Nicotine**, Benzene, , Asbestos)Asbestos)

Ultraviolet Ultraviolet radiationradiation

**Nicotine is not a carcinogen, but **Nicotine is not a carcinogen, but there are over 60 carcinogens in there are over 60 carcinogens in tobacco smoketobacco smoke

The ozone absorbs some, but not all of the types of UV radiation:

UVA: Not absorbed by the ozone layer.

UVB: Mostly absorbed by the ozone, but some does reach the Earth’s surface.

UVC: Completely absorbed by the ozone layer and oxygen.

UVA and UVB that reach the Earth’s surface contribute to serious health effects.

Radiation Radiation (Electromagnetic (Electromagnetic Spectrum)Spectrum)– SongSong– NASA’s NASA’s

Imagine the Imagine the Universe!Universe!

– And cancer And cancer (American (American Cancer Cancer Society)Society)

Causes of Cancer:Causes of Cancer:

These are called These are called carcinogenscarcinogens: : cancer-causing agents (also called cancer-causing agents (also called mutagens)mutagens)– Exposure to these Carcinogens is Exposure to these Carcinogens is

cumulativecumulative, meaning the longer , meaning the longer you’re exposed the greater your risk.you’re exposed the greater your risk.

– Carcinogens attack DNA and Carcinogens attack DNA and mutate mutate the genesthe genes that controls cell division that controls cell division These “control” genes are called These “control” genes are called oncogenesoncogenes

Kinds of Tumors:Kinds of Tumors:

BenignBenign: Harmless because do not : Harmless because do not spread to other tissues of the bodyspread to other tissues of the body– Ex. Ex. WartsWarts (caused by a virus) (caused by a virus)

Kinds of Tumors:Kinds of Tumors:

MalignantMalignant: = : = CANCERCANCER– Very dangerousVery dangerous

– Spreads to different Spreads to different kinds of tissues kinds of tissues (called (called metastasismetastasis))

– Interferes with Interferes with organorgan functionfunction

CancerCancer

Cancer cells do not carry on Cancer cells do not carry on normal functions, all their normal functions, all their energy goes into dividingenergy goes into dividing. .

They also They also use up the use up the nutrientsnutrients for cells so they for cells so they can’t do their job as well.can’t do their job as well.

Cancer TreatmentsCancer Treatments

SurgerySurgery:: removal of cancerous removal of cancerous cells, hopefully before it can spread.cells, hopefully before it can spread.

Radiation TherapyRadiation Therapy:: burn and/or burn and/or killkill all cells in the areaall cells in the area

ChemotherapyChemotherapy:: medication that medication that destroy all rapidly destroy all rapidly dividing cellsdividing cells (including cells that (including cells that grow hair, line the grow hair, line the gut, produce sperm, gut, produce sperm, produce nails, produce nails, produce blood cells)produce blood cells)

Cancer TreatmentsCancer Treatments

So…So…

There are many different forms of cancer, all There are many different forms of cancer, all with varying threat levels to a person’s with varying threat levels to a person’s health. A person’s susceptibility and ability to health. A person’s susceptibility and ability to fight cancer depend on their health, physical fight cancer depend on their health, physical activities, heredity, the environment they live activities, heredity, the environment they live in and access to health care. in and access to health care.

In short, Cancer, in all its various forms, is In short, Cancer, in all its various forms, is uncontrolled cell division that leads to a uncontrolled cell division that leads to a tumor with the ability to spread to different tumor with the ability to spread to different tissues in the body. tissues in the body.

Dear 16 Year Old MeDear 16 Year Old Me