Biomedical Technology Cell Biology and Cancer Objective 2 Causes and Development of Cancer

What causes cancer? The Known Agents Ultraviolet Radiation Radium Coal tar Cigarette Smoke Asbestoses

What does cancer represent? It represents a breakdown of the processes that regulate the growth of normal cells and tissues.

What happens when a person develops cancer? Cancer cells multiply rapidly, taking up space and nutrients from the normal cells.

A once precisely regulated system of cell division goes wild ! Cancerous growth disrupts and allows uncontrolled division of body cells.

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.

The Stages of Tumor Development Tumors: A mass of cancer cells 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 disrupts the tissues and organs needed for survival.