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Scientific/Medical Question 12
What are the key features of cancerous cells and what are the routes through which cancers can spread?
Cancer cells have an irregular cell shape and multiple enlarged nucleoli. They exhibit uncontrolled growth, being self-sufficient in growth signals and with insensitivity to anti-growth signals. They also remain immature and undifferentiated (i.e. they do not develop into a mature cell), and resist programmed cell death. They also have the ability to spread throughout the body (metastasise).
Metastasis occurs through four routes.
Lymphatic spread is the transport of tumour cells to regional lymph nodes near the tumour, and eventually throughout the body. The nearest node to the primary tumour is called the sentinel lymph node Hematogenous metastasis is spread through blood vessels - typically via veins rather than arteries. Transcoelemic metastasis involves spread into the cavities of the body; canalicular spread involves spaces like the urinary system or bile ducts. Different cancer types will be more or less likely to spread through different routes.