PROLIFERAZIONE CELLULARE E RESISTENZA AI FARMACI

CANCER Cancer is characterized by abnormal, unrelated cell proliferation Cancer invades healthy tissues and compete with normal cells for oxygen, nutrients, and space Abnormal cells reproduce in the same way as normal cells, but they do not have the regulatory mechanisms to control growth The abnormal cell growth proliferates in an uncontrolled and unrestricted way.

CANCER Tumors are also classified according to their cell of origin and whether their growth is benign or malignant BENIGN tumors remain at their site of origin They may grow large, but their growth rate is slower than that of malignant tumors They usually do not cause death unless their location impairs the function of a vital organ MALIGNANT tumors grow rapidly are likely to undergo metastasis (See table 20-2)

Benign vs malignant

Epithelial cells = carcinomas Connective tissues or muscle = sarcomas Hemopoietic cells = leukemias Pigments producing cells of the skin = melanoma

6 key behaviors of cancer cells 1.They disregard the external and internal signals that regulate cell proliferation 2.They are resistant to apoptosis 3.The avoid limitations to proliferation, such as differentiation and senescence 4.They are genetically unstable 5.They are invasive (escape home tissue) 6.The metastasize (survive and proliferate in foreign tissues)

Clonal Evolution

Genetic Instability and Tumor Progression

Normal and deranged control of cell production from stem cells

Dominant and recessive cancer genes

Ways to make a proto-oncogene overactive

The genetic mechanisms underlying retinoblastoma

Rb Protein

Major signaling pathways relevant to cancer

p53

Telomerase is reactivated in Human cancers