Cancer is defined as an uncontrolled division or proliferation of cells without any differentiation. Repeated division of cells form a large mass of tissue called tumors. Tumors are of two types, i.e., benign (non-cancerous) and malignant (cancerous). The invasion of cancerous cells (in malignant tumors) from one part to the other parts of body is called metastasis, while metagenesis is the alteration of generation. Teratogenesis is a prenatal toxicity characterised by structural, functional defects in the developing embryo or foetus. Mitosis is a type of cell division that results in two daughter cells.