Immunohistochemical assessment of Ki-67 as prognostic cellular proliferation marker in anal canal carcinoma

In order to define new prognostic factors useful for therapeutic decision-m aking, the Authors conducted a study on anal canal carcinomas in which Ki-6 7 proliferation index is correlated with pathological variables and clinica l outcome. The Ki-67-detectable antigen is expressed in all stages of the c ells cycle except GO. Thus, Ki-67 index can measure cell proliferation and it could be considered an indicator of prognosis. Thirty-one patients with anal canal carcinoma were evaluated. The specimens were formalin-fixed, par affin-embedded and used for immunostaining of Ki-67 antigen. We found a sig nificant correlation between Ki-67 score and depth of invasion and lymph no de involvement. No correlation was found between high Ki-67 value and neopl astic relapse. These results suggest that Ki-67 positivity carries differen t significance in different cancers. Additional studies are required to asc ertain whether more aggressive therapeutic procedures should be applied in the subset of patients with a high growth fraction.