Purpose: To correlate the immunohistochemical expression of topoisomerase IIalpha (topoIIalpha) in Hodgkin's lymphoma (HL) with clinicopathological parameters, the expression of Ki-67 and the outcome of patients, who had been homogenously treated with ABVD or equivalent regimens.
Experimental design: Immunohistochemistry using the monoclonal antibody Ki-S1 (topoIIalpha) was performed in 238 HL patients. MiB1 (Ki-67) expression was evaluated in 211/238.
Results: The mean +/- SD percentage of topoIIalpha- and Ki-67-positive Hodgkin-Reed-Sternberg (HRS) cells was 63 +/- 19% (5%-98%) and 73 +/- 19% (8%-99%), respectively. The median percentage of topoIIalpha-positive HRS cells was 64% (interquartile range, 51-78%). There was no correlation between topoIIalpha expression and patient characteristics. TopoIIalpha and Ki-67 expression were correlated (Spearman's Rho 0.255, P < 0.001). TopoIlalpha expression within the highest quartile of this patient population was predictive of failure free survival (FFS) (10-year rates 82 +/- 3% vs 68 +/- 7%, P = 0.02 for patients falling into the quartiles 1-3 and 4 respectively). In multivariate analysis topoIIalpha expression was independently predictive of FFS.
Conclusion: TopoIIalpha was expressed in all cases of HL showing a correlation with Ki-67 expression. Under current standard therapy including drugs inhibiting its activity, topoIIalpha was an independent adverse predictor of FFS with no statistically significant correlation with other established prognostic factors.