Cellular and Molecular Basis of Cancer By Robert Peter Gale, MD, PhD, DSC (hc), Imperial College London Reviewed / Revised Sep 2022 View Patient Education Cellular Kinetics Cancer Growth and Metastasis The Immune System and Cancer Molecular Abnormalities Environmental Factors Immune Disorders Topic Resources The cell cycle Cancer-Associated Viruses Common Chemical Carcinogens Many factors are involved in causing and permitting the unregulated proliferation of cells that occurs in cancer.