Presentation on theme: "PROLIFERAZIONE CELLULARE E RESISTENZA AI FARMACI."— Presentation transcript:
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)
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)