Hanahan and Weinberg used term “Hallmarks of Cancer” to differentiate healthy cells from cancerous cells. The significant differences between healthy cells and cancerous cells provide foundation to wage the war against the cancer cells. The followings are Hallmarks of Cancer:

• Hallmark 1: Genetic Instability Cancer is considered to be a genetic disease. All cancer cells are genetically different from their parental healthy cells. Genetic mutation is one critical factor in the genesis of cancer. Cancer is not simply a homogeneous clone of cells. Cancer cell heterogeneity arises from multiple clones of cancer cells created through mutations. Genetic mutations in cancerous cells are greater than 10,000, although the cancer relevant number of mutations are about 1000.
• Hallmark 2: Self-Sufficiency in Growth Signals In cancerous cells, signaling molecules are over-expressed and growth signals are over-amplified, prompting uncontrolled division and cell growth.
• Hallmark 3: Sustained Angiogenesis Without blood supply, cancerous cells cannot survive. Cancerous cells are able to induce angiogenesis (new blood vessel formation), which provides resources for sustainable cancer growth.
• Hallmark 4: Insensitivity to Growth-Inhibitor Signals Cancerous cells ignore anti-growth signals and maintain replicative capacities.
• Hallmark 5: Evasion of Apoptosis Healthy cells have mechanisms to initiate apoptosis (programmed cell death). Cancerous cells lack such functions, resulting in defect in programmed cell death.
• Hallmark 6: Limitless Replicative Potential Cancerous cells acquire limitless replicative potential. Such cells are said to be immortal.
• Hallmark 7: Tissue Invasion and Metastasis The final stage of cancerous development is known as metastasis, the spreading of cancer to new locations in the body. Most of the cancer fatalities are caused by these secondary metastatic lesions because they cannot be cured by local therapies such as surgery or radiation.