Topoisomerase 1 (TOP1) is overexpression is correlated with an advanced cancer stage and poor survival in ovarian cancer patients.

<p>(A) Right, quantification according to nuclear IHC TOP1 expression in ovarian neoplasms compared with paired normal tissues. Left, representative images of IHC staining of cells expressing TOP1 in 30 paired specimens of neoplasm and normal tissues; The scores were calculated using the formula staining intensity × the percentage of stained cells. (B) Scores of 0–3+ indicating TOP1 levels in representative ovarian cancer tissues. (C) The Kaplan–Meier (KM) plot of the overall survival of 155 ovarian cancer patients, stratified on the basis of the TOP1 levels. (D) The KM plot of disease-free survival of 155 patients with ovarian cancer, stratified on the basis of TOP1 levels.