Immunohistochemical staining for DNA topoisomerase II in non-Hodgkin's lymphomas.

DNA topoisomerase II (topo II) is the target of several clinically useful anticancer drugs. Several of these agents, such as doxorubicin and etoposide (VP-16), are used to treat non-Hodgkin's lymphomas (NHL). To understand the therapeutic selectivity of these drugs, a series of 33 cases of NHL for topo II were analyzed using an immunohistochemical technique that detects the enzyme in formalin-fixed, paraffin-embedded tissue. The average topo II index of high grade (Working Formulation) NHL was 48.6 with a range from 24.4 to 79.7. The average topo II index of low grade (Working Formulation) NHL was 4.4 with a range from 0.9 to 11.2. These two values are statistically different (P < .01). The intermediate grade (Working Formulation) NHL are a heterogeneous group based on topo II staining. The average topo II index value for the intermediate grade neoplasms was 26.7 with a range from 1.4 to 54.9. Because the proliferation marker Ki-67 has been shown to be of prognostic importance when used in the analysis of NHL, 27 cases for also were analyzed for MIB1 (Ki-67). The average MIB1 index of the high grade NHL was 59.8 with a range from 40.7 to 80.3. This average is statistically different (P < .01) than the average MIB1 index of 11.2 (range 1.7-28.3) found in the low grade NHL. Similar to results with topo II, the intermediate grade NHL was a heterogeneous group of tumors with respect to MIBI staining and had an average MIB1 index of 49.1 with a range from 8.9 to 86.7. These results show that high grade NHL have topo II and MIB1 indices that are significantly higher than low grade NHL. Intermediate NHL are more heterogeneous and have topo II and MIB1 indices that range from low to high.

Immunohistochemical staining for DNA topoisomerase II in frozen and formalin-fixed paraffin-embedded human tissues.

DNA topoisomerase II is the molecular target of several clinically useful chemotherapeutic drugs. The sensitivity of cells to drugs that target topoisomerase II is dependent on the cellular content of this enzyme. Drug-sensitive cells have elevated amounts of type II topoisomerase. To determine relative amounts of enzyme in malignant neoplasms, we developed an in situ immunohistochemical stain for topoisomerase II. The stain uses either polyclonal or monoclonal antibodies produced against the alpha isoform of the enzyme. Staining can be done on both frozen and formalin-fixed, paraffin-embedded tissues. By using this immunostain, we found marked differences in enzyme content in several human malignancies.

Diagnosis of cytomegalovirus pneumonitis on bronchoalveolar lavage fluid: comparison of cytology, immunofluorescence, and in situ hybridization with viral isolation.

Forty-three bronchoalveolar lavage (BAL) specimens from 40 immunocompromised patients were studied for the presence of cytomegalovirus (CMV) by rapid diagnostic methods. DNA in situ hybridization, cytology, and immunofluorescence were compared to conventional cell culture. Eleven (25%) of the 43 BAL samples grew CMV in culture. In situ hybridization detected 6 of these 11 for sensitivity, specificity, and predictive values of positive and negative of 55%, 94%, 75%, and 86%, respectively. Cytology had a sensitivity of 73% and specificity of 100%. Six Papanicolaou-stained cytospins were screened cytologically versus one hybridization cytospin, and the higher sensitivity of cytology may reflect this extensive sampling. The immunofluorescent method had a sensitivity equal to that of cytology (73%): however, the specificity (72%) was significantly less than that of either the probe or cytology. These data suggest that although in situ hybridization can be a rapid, useful method for detecting CMV in BAL specimens, cytology appears to be a more sensitive method.