Physiology of Cancer: Prospective Aspects beyond the 21st Century

Abstract

Cancer is an aggressive disease and is the major cause of death worldwide. There are several factors involving in carcinogenesis and these factors cause cellular genetic alteration. Consequently, normal cells with genetic alteration transform to cancer cells. Normal cells have strict regulation of growth to preserve appropriate proportion of cells. There are 3 processes influencing on the proportion of cells (proliferation, differentiation, senescence and apoptosis). If there is any factors disturbing these 3 processes causing abnormal growth, cancer is occurred. There are 2 theories proposed to explain carcinogenesis (cancer stem cell model and clonal evolution model). Presently, many evidence support the existence of cancer stem cells discovered in many types of cancer. Cancer stem cells are believed to cause tumor relapse, distant metastasis and multidrug resistance. Hence, cancer therapy focuses on targeting cancer stem cell population with targeted therapy to specifically get rid of only cancer cells and have less toxic effects to normal cells. In the next century, the trend of cancer treatment is personalised oncology, which evaluates the characteristics of individual cancer patients to receive the most appropriate drugs with less toxicity rather than one drug for all patients who have similar malignant disease. Due to the fact that each cancer type has variation of genetic alteration and patients have different causes of carcinogenesis. Consequently, patients with similar cancer type have different levels of disease aggressiveness and different levels of drug response. Prognostic biomarkers and genetic test are used to indicate appropriate treatment for cancer patients with personalised medicine.