Transition of ki‐67 index of uterine cervical tumors during radiation therapy. Immunohistochemical study

Abstract

Histopathologic and Ki‐67‐staining features of cancer cells were investigated in biopsy specimens before and during radiation therapy in 29 patients with cervical squamous cell carcinoma. No morphologic changes were observed up to doses of 540 cGy. A few intact cancer cells remained up to doses of 2700 cGy. Moderate changes in the cancer cells were noticed in patients who received 900 cGy or more, i.e., multinuclei, swollen nuclei and cytoplasms, and prominent large nucleoli. At doses of 1800 cGy or greater, many cancer nests had severely damaged cancer cells with features such as cytolysis, karyolysis, karyorrhexis, pyknosis, and bizarre giant cells. There was no mitosis in the cells of patients who received doses greater than 1800 cGy. The Ki‐67‐positive cancer cells showed diffuse nuclear‐stainings and dot‐stainings before radiation therapy. Radiation doses more than 900 cGy changed the staining pattern of the Ki‐67 antibody; large irregular spot‐stainings and ring‐stainings were observed predominantly. The Ki‐67 index initially increased with the radiation dose; the mean Ki‐67 indices before radiation therapy and at radiation doses of 180 cGy, 540 cGy, and 900 cGy were 41%, 50%, 63%, and 68%, respectively. The indices decreased when the dose was increased further, and they were 39% and 20% at doses of 1800 cGy and 2700 cGy, respectively. Possible explanations, including recruitment of quiescent cells, for the change in Ki‐67 staining are discussed. Copyright © 1991 American Cancer Society