Apoptosis in skin cancer development and regression.

Non-melanoma skin cancers (NMSC) are the most common malignant tumors in white population and their incidence has been increasing worldwide. Molecular events regulating cell survival, apoptosis, growth arrest as well as cell differentiation, are important contributors to the overall kinetics of benign and malignant cell growth and play a role in their development, progression and regression. Failure of these pathways can result in the loss of control over proliferation and lead to tumor development through the inactivation of tumor suppressor genes or the activation of oncogenes. Also, immunological mechanisms have been implicated in a phenomenon of tumor progression as well as spontaneous tumor regression. We have tried to summarize the main events in etiopatogenesis, development, progression and in some cases skin cancer regression. Further studies are needed to elucidate completely the details of apoptotic control in normal skin and determine factors resulting in apoptotic disbalance and disease.