The lung, in particular the bronchial epithelium, is a major site for tumor formation in
humans. Environmental factors, such as cigarette smoke, in conjunction with genetic factors
are important determinants in this disease. Malignant cells exhibit alterations in their control
of proliferation and differentiation. It is believed that the acquisition of defects in the
regulation of these processes is important in the process of carcinogenesis. A clear insight
into the basic mechanisms of the regulation of proliferation and differentiation is required to …