Clinical utility of chromosome 17 alpha satellite probe in distinguishing benign mesothelium from malignant cells: a...

Fluorescent in situ hybridization has shown promise in detecting malignant cells in body cavity effusions. However, this requires special preparatory techniques not used in many laboratories. We developed an in situ hybridization (ISH) procedure specifically for ethanol-fixed specimens, and using it tested the clinical utility of the chromosome 17alpha satellite probe (C17alpha). ISH with C17alpha was used in 12 malignant and 10 benign ethanol-fixed body cavity effusions. Cells were pretreated with protease K prior to ISH. The probe was detected by an anti-digoxigenin-horseradish peroxidase method. Signals were counted in 100 nuclei and the chromosome index (CI) and percent diploid cells calculated in each case. ISH was successfully performed in all cases. Malignant cells had an average CI of 2.23 with less than 44% diploid nuclei and 50% of specimens exhibited bizarre signals. Benign effusions had an average CI of 1.98 with over 84.6% diploid nuclei. Questionably bizarre signals were seen in two (20%) benign specimens. ISH can be performed on ethanol-fixed specimens. The C17alpha probe may prove valuable in detecting malignant cells in body cavity effusions.