5 - Role of Immunohistochemical Expression of Ki-67 in Adenocarcinoma of Large Intestine

This chapter discusses the results of multiannual studies on large intestine carcinoma, describing the role of Ki-67 antigen expression, in correlation with selected clinicopathologic parameters. The expression of metallothionein (MT), the protein affecting proliferation, and differentiation of cells is also discussed in the chapter. The intensities of Ki-67 and MT antigen expression are compared with the intensity of apoptosis in cells of large intestine adenocarcinoma. Tumor growth and progression represent the result of its proliferative activity and the capacity of eliminating cancer cells by apoptosis, necrosis, or both. Intensified proliferation of neoplastic cells leads to augmented volume and mass of the tumor that may induce, within the tumor processes, leading to apoptosis and necrosis. The exponents of apoptosis may indirectly provide the markers of intensity of tumor cell proliferation. In large-intestine adenocarcinomas the parallel expression of Ki-67 antigen, intensity of apoptotic process (terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling [TUNEL]), and immunohistochemical expression of cas-3 is described in the chapter. The application of Ki-67 antigen is used as an index of sensitivity to chemotherapy. Tumors of a high proliferative index and exhibiting intense Ki-67 expression are found to be more sensitive to chemotherapy and radiotherapy.