Biomedical Technology

Cell Biology and CancerObjective 2

Causes and

Development of Cancer

What causes cancer?The Known Agents

Ultraviolet Radiation

RadiumCoal tarCigarette SmokeAsbestoses

What does cancer represent?

It represents abreakdown of theprocesses thatregulate the growthof normal cells andtissues.

What happens when a person develops cancer?

Cancer cells multiply rapidly, taking up

space and nutrients from the normalcells.

A once precisely regulated system of cell division goes wild !

Cancerous growth

disrupts and allows

uncontrolleddivision of bodycells.

How exactly does cancer cause all this trouble? First: Look at “Normal Cell Division”

• Cell division rate is normally controlled by

two genes.

• These genes are able to send messages from cell to cell telling them when to replicate, when to stay the same or when to die.

• The genes regulate cell growth by activating the “cell cycle clock” found in each cell body.

• Cancer gains control or disrupts this mechanism and the result is overcrowding and inadequate nutrition to support the increased cell growth.

Introducing !

The Stages of Tumor

Development

Tumors: A mass of cancer cells

Stage 1: Mutation

• The first stage of cancer

• The mutation starts in the genetic make up of the cells

• Causes cells to start multiplying and dividing more rapidly that it normally would.

Stage 2: Hyperplasia

• Second stage of cancer development

• Enlargement of a part due to an abnormal numerical increase of its cells.

• Increase of number of cells leads to enlargement of tissue or organ involved.

• Considered a pre-cancerous stage.

Stage 3: Dysplasia

• Abnormal cells that are not cancer

• Starts to increase the size of tissue or organ

Stage 4: In Situ cancer (tumor)• Cancer that has

remained within the original tissue where it started.

• Has not started to spread to other parts or tissues surrounding it.

Early detection catches cancer in this stage

Stage 5: Invasive cancer (malignant)

• Invades nearby tissues

• Cells can shed from the primary tumor into the blood or lymph and invade other parts of the body.

Tumors threaten an individual’s

life when their growth disruptsthe tissues and organs neededfor survival.