  This paper explores fluctuations and noise in various facets of cancer
development. The three areas of particular focus are the stochastic progression
of cells to cancer, fluctuations of the tumor size during treatment, and noise
in cancer cell signalling. We explore the stochastic dynamics of tumor growth
and response to treatment using a Markov model, and fluctutions in tumor size
in response to treatment using partial differential equations. We also explore
noise within gene networks in cancer cells, and noise in inter-cell signalling.
