Uncontrolled cell growth and survival Cancer Uncontrolled cell growth and survival

Two Types of Tumors Benign (noncancerous) Look like cells around them Have controls that prevent infinite division Stay local Malignant Cells shaped improperly Have lost controls that prevent cell division Can metastasize Normal fibroblast cell vs. Malignant fibroblast cell

Metastasis Primary cancer cells can release signals to start growth of blood vessels (angiogenesis) Cancer cells get nutrients, oxygen, and a passageway to elsewhere in the body Secondary tumors result when cancer cells find a new home and thrive

Metastasis

Why Tumors are Harmful Mutated cells can’t carry out normal functions (are not specialized) Mutated cells crowd out normal cells Mutated cells use up nutrients normal cells need

Carcinogens-chemical, physical, or biological agents that cause cancer UV radiation Tobacco Some viruses (i.e. human papillomavirus- HPV) Some toxins & chemicals How do these all cause cancer? They damage DNA!!! Cancers result if they damage tumor suppressor genes or proto-oncogenes

What types of genes do carcinogens mutate? Unit 5 - Reproduction (Topics 3-4) OBJ 12 What types of genes do carcinogens mutate? Proto-Oncogenes Normal proteins stimulate cell division (Like the gas pedal) Cause the cell to move into S phase Mutation activates them permanently, turning them into “oncogenes” Tumor Suppressor Genes Normal proteins block cell growth and division (Like the brakes) Mutations turns these genes off (inability to stop cell division) p53 is an example (on chromosome 17) Oncogenes are the mutated version of growth promoting genes: they have improved function, and encourage excess growth

Unit 5 - Reproduction (Topics 3-4) OBJ 12 What does p53 do normally? p53 is mutated in about 50% of human tumor cells

Unit 5 - Reproduction (Topics 3-4)