In a 2000 article by
Hanahan and Weinberg, the biological properties of malignant
tumor cells were summarized as follows:
Acquisition of self-sufficiency in growth signals, leading to
unchecked growth.
Loss of sensitivity to anti-growth signals, also leading to
unchecked growth.
Loss of capacity for apoptosis, in order to allow growth despite
genetic errors and external anti-growth signals.
Loss of capacity for senescence, leading to limitless
replicative potential (immortality)
Acquisition of sustained angiogenesis, allowing the tumor to
grow beyond the limitations of passive nutrient diffusion.
Acquisition of ability to invade neighbouring tissues, the
defining property of invasive carcinoma.
Acquisition of ability to build metastases at distant sites, the
classical property of malignant tumors (carcinomas or others).
The completion of these multiple steps would be a very rare
event without :
Loss of capacity to repair genetic errors, leading to an
increased mutation rate (genomic instability), thus accelerating
all the other changes.
These biological changes are classical in carcinomas; other
malignant tumor may not need all to achieve them all. For
example, tissue invasion and displacement to distant sites are
normal properties of leukocytes; these steps are not needed in
the development of Leukemia. The different steps do not
necessarily represent individual mutations. For example,
inactivation of a single gene, coding for the P53 protein, will
cause genomic instability, evasion of apoptosis and increased
angiogenesis.
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Cancer
Classification
1. Nomenclature
2. Adult cancers
3. Childhood cancers
Signs and symptoms
Diagnosis
1. Investigation
2. Biopsy
Treatment
1. Surgery
2. Radiation therapy
3. Chemotherapy
4. Targeted therapies
5. Immunotherapy
6. Hormonal therapy
7. Symptom control
8. Complementary and alternative
9. Treatment trials
Prognosis
1. Emotional impact
Causes
1. Chemical carcinogens
2. Ionizing radiation &
Infectious diseases
3. Hormonal imbalances
& Immune system dysfunction
4. Heredity & Other causes
Pathophysiology
1. Epigenetics
2. Oncogenes
3. Tumor suppressor genes
4. Cancer cell biology
4.1 Clonal evolution
4.2 Biological properties of cancer cells
Prevention
1. Modifiable ("lifestyle") risk factors
2. Diet
3. Vitamins
4. Chemoprevention
5. Genetic testing
6. Vaccination
7. Screening
Epidemiology
History
Research |
