4. Hallmarks of Cancer (part 1)

The hallmarks of cancer are a list of properties that cancerous cells all have in common. These properties are behaviours gained through mutations to genes that produce proteins that function to provide them with these abilities:

They include:
1. self sufficient growth
2. insensitivity to anti-growth signals
3. tissue invasion and metastasis
4. limitless replicative potential
5. sustained angiogenesis
6. avoiding apoptosis

This video covers the first 2 hallmarks.

Cell division in the body is normally very tightly controlled to ensure that tissues in the body – which are made up of cells – grow in the co-ordinated fashion. Cells normally need signals from other cells to tell them when to divide. When cells break free of these controls, and start dividing even when they are not getting these signals, they begin to divide uncontrollably and neoplasms (also known as tumours) result.

Tissues normally regulate their size by controlling the number of cells which are allowed to enter the cell cycle and divide. This is controlled at various points along the cycle called checkpoints. Cancerous cells are able to ignore signals that would normally stop them at these checkpoints. In addition to this, cells with DNA damage, which would include all potentially cancerous cells, are usually stopped at these checkpoints to avoid them diving and passing on their mutations. Cancerous cells are able to pass checkpoints by avoiding these mechanisms.

References
Hanahan and Weinberg, 2000 The hallmarks of cancer Cell, 100 (2000), pp. 57-70