The document discusses the roles of cloud-based systems in cancer studies. It describes how cloud computing provides computing services over the internet to offer flexible resources and lower costs. The document then covers six main types of cancer (colon, lung, ovarian, breast, skin, and prostate) that have been studied using cloud computing. It examines several methods used for cancer classification in the cloud, as well as open issues and future work around data security and management. The conclusion states that cloud computing improves access to medical records, accuracy of diagnostics, and ability to identify illnesses early.