Errors in Cell DivisionCancer

Out of control cell division What happens when a cell doesn’t destroy itself? What happens when a cell doesn‘t stop dividing?

Terminology Cancer: a group of diseases in which

cells undergo uncontrolled division Tumour: mass of cells that grow and

divide without any obvious function in the body

Benign tumour: cells stay together having no effect on surrounding tissue other than physical crowding

Malignant tumour: cells interfere with the function of surrounding cells

Characteristics of Cancer Cells

Rapid cell division Uses energy and resources of other cells Does no useful work of its own May undergo metastasis: cancer cells that

break away from the original location and move through the blood stream to a secondary location

Click on picture for animation

Cause of Cancer: Mutations

Genetic mutations in the parts of the DNA responsible for regulating the cell cycle

Loss of 1 or more cell cycle checkpoints

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Results of Mutation

Cell spends less time in interphase

Continuous mitosis

Rapid cell division

Carcinogens Environmental factors that cause

cancerTypes ExamplesViral Hepatitis B (liver

cancer)HPV (cervical cancer)

Ionizing radiation

Nuclear falloutX-raysSun (skin cancer)

Mutagenic chemicals

Cigarette (lung cancer)

Diagnosing Cancer: Imaging technologies Endoscopy X-ray Ultrasound CT/CAT scan (computerized axial

tomography) MRI (magnetic resonance imaging)

Imaging Technology: Endoscopy

Fiber-optic cable delivers a camera with light into the body and send images to a screen

Visual identification of abnormalities

Sometimes forceps are at the end so that tissue can also be removed

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Imaging Technology: Endoscopy

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Imaging Technology: X-rays Useful for bones and

lungs Disadvantage: X-

rays can cause DNA damage

Think: Why are x-rays

especially damaging to rapidly dividing cells?

Who should avoid x-rays?

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Imaging Technology: X-rays

Mammogram: specialized x-ray for imaging breast tissue

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Imaging Technology: Ultrasound Use high frequency sound waves to

create an image Useful for looking at soft tissue

Imaging Technology: Ultrasound

12 weeks

Head

Hands

Heart

Imaging Technology: Ultrasound

26 weeks

Head

Mouth

Eyes

Eyes

Imaging Technology: CT scan CT or CAT scan:

computerized axial tomography

Uses x-ray technology Many images are

taken from different angles

Images are assembled by a computer to form a series (i.e. like a flip book)

CT scan animationBrain tumor, 3D CT scan. In the 3D scan the brain is red, bone is blue and the tumour is green (on the top left)

Imaging Technology: CT scan

Imaging Technology: MRI Magnetic resonance imaging Uses radio waves and a strong

magnetic field to created detailed images

Computer assembles the information into a 3-dimensional model

Imaging Technology: MRI

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Diagnosing Cancer: Biopsy

A sample of tissue is removed and analyzed to determine what it is

CT scan animation

Diagnosing Cancer: Biopsy

CT scan animation

Diagnosing Cancer: Biopsy

CT scan animation

Reducing Risk: Screening Important for those with a family

history of cancer Does not prevent cancer but increase

the chance of detecting it early to treat it

Examples: self-examination, blood tests etc.

Some common screening: Breast exam for breast cancer Pap smear for cervical cancer

Reducing Risk: Lifestyle Choice Healthy diet “super foods” Reduce body fat Not smoking

Cancer Treatments Surgery: physical removal of tumour Chemotherapy Radiation therapy

Cancer Treatment: Surgery

Cancer Treatment: Chemotherapy

a combination of drugs that kill rapidly dividing cells

can also affect normal rapidly dividing cells (e.g. hair follicle, intestinal cells)

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Cancer Treatment: Radiation Therapy

Using high energy radiation to kill cancer cells but can also damage normal cells

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