a

R

Understanding Cancer and Related TopicsUnderstanding Cancer

Developed by:Lewis J. Kleinsmith, Ph.D.Donna Kerrigan, M.S.Jeanne KellyBrian HollenDiscusses and illustrates what cancer is, explains the link between genes and cancer, and discusses what is known about the causes, detection, and diagnosis of the disease.

These PowerPoint slides are not locked files. You can mix and match slides from different tutorials as you prepare your own lectures. In the Notes section, you will find explanations of the graphics. The art in this tutorial is copyrighted and may not be reused for commercial gain.Please do not remove the NCI logo or the copyright mark from any slide. These tutorials may be copied only if they are distributed free of charge for educational purposes.

a

R

What Is Cancer?

a

R

Different Kinds of Cancer

Lung

Breast (women)

Colon

BladderProstate (men)

Some common sarcomas:FatBone

Muscle

Lymphomas:Lymph nodes

Leukemias:Bloodstream

Some common carcinomas:

a

R

Naming Cancers

Prefix Meaningadeno- glandchondro- cartilageerythro- red blood cellhemangio- blood vesselshepato- liverlipo- fatlympho- lymphocytemelano- pigment cellmyelo- bone marrowmyo- muscleosteo- bone

Cancer Prefixes Point to Location

a

R

Loss of Normal Growth Control

Cancer cell division

Fourth orlater mutation

Third mutation

Second mutation

First mutation

Uncontrolled growth

Cell Suicide or Apoptosis

Cell damage—no repair

Normal cell division

a

R

Example of Normal Growth

Cell migration

Dermis

Dividing cells in basal layer

Dead cells shed from

outer surface

Epidermis

a

R

The Beginning of Cancerous Growth

Underlying tissue

During the development of skin cancer, the normal balance between cell division and cell loss is disrupted. The basal cells now divide faster than is needed to replenish the cells being shed from the surface of the skin. Each time one of these basal cells divides, the two newly formed cells will often retain the capacity to divide, thereby leading to an increase in the total number of dividing cells.

a

R

Tumors (Neoplasms)

Underlying tissue

a

R

Invasion and Metastasis

3Cancer cells reinvade and grow at new location

1Cancer cells invade surrounding tissues and blood vessels

2Cancer cells are transported by the circulatory system to distant sites

a

R

Malignant versus Benign Tumors

Malignant (cancer) cells invade neighboring tissues, enter blood vessels, and metastasize to different sites

Time

Benign (not cancer) tumor cells grow only locally and cannot spread by invasion or metastasis

a

R

Why Cancer Is Potentially Dangerous

Melanoma cells travel through bloodstream

Melanoma(initial tumor)

Brain

Liver

a

R

Genes and Cancer

Chromosomes are DNA molecules

Heredity

RadiationChemicals

Viruses

a

R

DNA Structure

DNA molecule

Chemicalbases

GC

TA

a

R

DNA Mutation

Additions

Deletions

Normal gene

Single base change

DNA

CT

A G C G A A C TAC

A G G C G C T AAC A C T

A G C T A A C TAC

A G A A C TAC

a

R

Oncogenes

Mutated/damaged oncogene

Oncogenes accelerate cell growth and division

Cancer cell

Normal cell Normal genes regulate cell growth

a

R

Proto-Oncogenes and Normal Cell Growth

Receptor

Normal Growth-Control Pathway

DNA

Cell proliferation

Cell nucleus

Transcriptionfactors

Signaling enzymes

Growth factor

a

R

Oncogenes areMutant Forms of Proto-Oncogenes

Cell proliferation driven by internal oncogene signaling

Transcription

Activated gene regulatory protein

Inactive intracellular signaling protein

Signaling protein from active oncogene

Inactive growth factor receptor

a

R

Tumor Suppressor Genes

Normal genes prevent cancer

Remove or inactivate tumor suppressor genes

Mutated/inactivated tumor suppressor genes

Damage to both genes leads to cancer

Cancer cell

Normal cell

a

R

Tumor Suppressor GenesAct Like a Brake Pedal

Tumor Suppressor Gene Proteins

DNACell nucleus

Signalingenzymes

Growth factor

Receptor

Transcriptionfactors

Cell proliferation

a

R

p53 Tumor Suppressor ProteinTriggers Cell Suicide

Normal cell Cell suicide(Apoptosis)

p53 protein

Excessive DNA damage

a

R

DNA Repair Genes

Cancer

No cancer

No DNA repair

Normal DNA repair

Base pair mismatch

T CATC

A GTCG

T CAGC

A GTCG

A GTG A GTAG

T CATCT CATC

a

R

Cancer Tends to Involve Multiple MutationsMalignant cells invade neighboring tissues, enter blood vessels, and metastasize to different sites

More mutations, more genetic instability, metastatic disease

Proto-oncogenes mutate to oncogenes

Mutations inactivate DNA repair genes

Cells proliferate

Mutation inactivates suppressor gene

Benign tumor cells grow only locally and cannot spread by invasion or metastasis

Time

a

R

Mutations and Cancer

Genes Implicated in Cancer

a

R

Cancer Tends toCorrupt Surrounding Environment

Growth factors = proliferation

Blood vessel

Proteases

Cytokines

Matrix

Fibroblasts, adipocytes

Invasive

Cytokines, proteases = migration & invasion

a

R

We would like to hear from you . . .If you have questions about this tutorial’s content, suggestions for new topics, or other feedback on the Web site, please send an e-mail to kerrigad@mail.nih.gov.If you have questions about this tutorial’s artwork or want permission to use it, please send an e-mail to beankelly@verizon.net.