Cancer Biology: Self-Sufficiency in Growth Signals

Study Notes

Normal cells require growth signals to proliferate and survive
Cancer cells acquire the ability to grow and divide without these external signals, becoming self-sufficient

Autocrine signaling: Cancer cells produce their own growth factors, stimulating their own growth and proliferation
Constitutive activation: Cancer cells have constitutively active growth factor receptors, allowing them to respond to growth signals even when they are not present
Bypass of normal checkpoints: Cancer cells can bypass normal cell cycle checkpoints, allowing them to continue growing and dividing despite DNA damage or other abnormalities

Autocrine growth factor production: Cancer cells producing platelet-derived growth factor (PDGF), epidermal growth factor (EGF), or transforming growth factor-alpha (TGF-α) to stimulate their own growth
Mutations in growth factor receptors: Activating mutations in receptors such as HER2 or EGFR, leading to constitutive activation and uncontrolled growth

Uncontrolled growth and proliferation: Cancer cells can grow and divide rapidly, leading to tumor formation and progression
Resistance to anti-growth signals: Cancer cells can become resistant to anti-growth signals, such as TGF-β, which normally inhibit cell growth and division

Normal cells rely on external growth signals to proliferate and survive
Cancer cells acquire ability to grow and divide without external signals, becoming self-sufficient

Cancer cells produce their own growth factors, stimulating their own growth and proliferation through autocrine signaling
Constitutively active growth factor receptors in cancer cells allow them to respond to growth signals even when not present
Cancer cells can bypass normal cell cycle checkpoints, continuing to grow and divide despite DNA damage or other abnormalities

Cancer cells produce platelet-derived growth factor (PDGF), epidermal growth factor (EGF), or transforming growth factor-alpha (TGF-α) to stimulate their own growth
Examples of autocrine growth factor production include PDGF, EGF, and TGF-α

Activating mutations in receptors such as HER2 or EGFR lead to constitutive activation and uncontrolled growth
Mutations in growth factor receptors result in continuous signaling, driving cancer cell growth and proliferation

Uncontrolled growth and proliferation of cancer cells lead to tumor formation and progression
Cancer cells become resistant to anti-growth signals, such as TGF-β, which normally inhibit cell growth and division