The body is a society whose members are cells, organized into tissues The body is a society whose members are cells, organized into tissues Cancer cells grow when they should not Cancer cells grow when they should not Cancer cells invade other tissues Cancer cells invade other tissues These are the behaviors of free growing cells, like bacteria These are the behaviors of free growing cells, like bacteria
Types of Tumors Benign Malignant Grow slowly as a single mass Grow rapidly and invade other tissues
90% of mutagens are carcinogens An environmental insult leads to DNA damage An environmental insult leads to DNA damage This results in a mutation…a change in DNA sequence This results in a mutation…a change in DNA sequence This mutation often alters cell proliferation This mutation often alters cell proliferation The cancer cells grows out of control The cancer cells grows out of control
One mutation alone does not lead to cancer There are cell divisions in a human lifetime Rate of spontaneous mutation = /gene/division Every gene will have mutations in an average lifetime
Cancer cells develop slowly Smoking leads to lung cancer Smoking leads to lung cancer 10 to 20 years Radiation exposure (the bomb) causes leukemias Radiation exposure (the bomb) causes leukemias 5 to 8 years
Cancer as a function of age
Genes implicated in cancer Oncogenes Tumor supressor genes DNA repair genes
Genes supressores de tumores Estes genes inibem normalmente o crescimento, a diferenciação ou a divisão celulares Estes genes inibem normalmente o crescimento, a diferenciação ou a divisão celulares A mutação provoca uma perda de função A mutação provoca uma perda de função Ambas as cópias do gene são mutadas (recessivos) Ambas as cópias do gene são mutadas (recessivos) Examplo: gene Rb Examplo: gene Rb Mutações no Rb provocam retinoblastomas Mutações no Rb provocam retinoblastomas
Mutações no gene Rb podem conduzir ao retinoblastoma X XXXX XX XX
O p53 é um gene supressor de tumores Most people with an alelle of p53 mutated develops cancer