Detection of hyperdiploid malignant cells in pleural effusions with chromosome-specific probes and fluorescence in situ hybridization.

OBJECTIVE

To compare the efficacy of fluorescence in situ hybridization (FISH) by using chromosome-specific probes with standard cytology and cytogenetics for detection of hyperdiploid malignant cells in pleural effusions.

MATERIAL AND METHODS

A blind study was done on 26 pleural effusions from 25 patients who had undergone thoracentesis (14 with and 11 without a malignant condition). Cytology, cytogenetics, and FISH with probes specific for chromosomes 7, 8, 12, 18, X, and Y were done on each pleural effusion. For FISH studies, malignant specimens were defined as having 8% or more of cells with hyperdiploidy.

RESULTS

Results of cytology and FISH were both normal in each of the 11 patients with benign pleural effusions. Cytogenetic studies were successful in six of these patients: five were chromosomally normal, but one male patient had an abnormal clone that lacked a Y chromosome. Among the 14 patients with malignant pleural effusions, cytology and FISH were abnormal in 8 and 6, respectively. Cytogenetic studies were successful in 11 of these patients, and an abnormal clone was found in 5.

CONCLUSION

FISH can detect hyperdiploid malignant cells in pleural effusions and can be useful in the work-up of patients suspected of having malignant pleural effusions.