DNA topoisomerase II-alpha in pulmonary carcinoid tumors

Fifty-four pulmonary carcinoid tumors of surgically treated patients were d iagnosed according to modified Arrigoni histological criteria (WHO 1999). F orty-seven typical (TC) and seven atypical carcinoids (AC) formed the basic groups. Four subgroups were selected from the TCs and consisted of cases w ith higher tumor size (T2.) or those associated with nodal involvement (N1) , tumor satellites, and tumorlets. Subgroup tumors were regarded as affecti ons with possible increased proliferation potential. The proliferate activi ty was examined immunohistochemically by topoisomerase II-alpha (clone SWT3 D1) on paraffin material and calculated by the number of positive nuclei pe r 10 HPF The topoisomerase expression was found to be statistically differe nt in both principal groups made up of typical and atypical carcinoids with a mean value of 49 and 135 positive nuclei per 10 high power field in TC a nd AC, respectively. The remaining subgroups of the TCs associated with exa mined characteristics (larger tumor diameter, metastases, satellites, tumor lets) were not found to be statistically different. The topoisomerase II-al pha is a marker giving valuable information about the diagnosis of pulmonar y typical and atypical carcinoids.