FISH in the evaluation of pleural and ascitic fluids

Pleural and ascitic fluids (PAF) are complications of both nonmalignant and malignant conditions, such as congestive heart failure and chronic infections, as well as neoplasias, such as mesothelioma, lymphoma, and adenocarcinomas of the lung, ovary, endometrium, breast, colon, stomach, and pancreas. Differentiation between malignant and nonmalignant PAF is not always easy to assess on the basis of clinical, cytologic, and other criteria. A review of the chromosomal anomalies in neoplasms which can cause PAF revealed aneusomies of chromosomes 1, 3, 7, 8, 10, and 11 in about 40% to 80% of these malignancies. We performed FISH using centromere-specific probes for chromosomes 1, 3, 7, 8, 10, and 11 and chromosomal analysis on PAF cells from 21 patients, including 3 with ovarian cancer, 2 with lymphoma, 5 with adenocarcinoma of unknown origin, 1 with breast cancer, and 10 with atypical lymphocytosis of unknown cause. The results indicate a) a high correspondence between FISH and the clinical diagnosis (9 of the 11 cases of malignant fluid showing FISH abnormalities); b) that FISH is more sensitive than cytogenetics in detecting abnormal clones (10 vs. 6); and c) that FISH is a valuable adjunct to cytology in the interpretation of atypical lymphocytosis (3 of the 10 cases were shown to be abnormal by FISH). Thus, the FISH technique can be a very useful adjunct to conventional cytogenetics in yielding crucial information on the origin of PAF.