Interphase fluorescence in situ hybridization improves the detection of malignant cells in effusions from breast cancer patients.

In diagnostic evaluation of effusions, difficulties are encountered when atypical reactive mesothelial cells have to be differentiated from malignant cells. We tested the impact of fluorescence in situ hybridization (FISH) to identify metastatic cells in breast cancer effusions by detection of numerical chromosomal changes. Pleural and ascitic fluid samples (n=57) from 41 breast cancer patients were concomitantly evaluated by routine cytology and FISH, using centromere-specific probes representing chromosomes 7, 11, 12, 17 and 18. After setting stringent cut-off levels deduced from non-malignant control effusions (n=9), the rates of cells with true aneuploidy were determined in each effusion sample from breast cancer patients. The occurrence of aneuploid cells, as detected by FISH and indicative of malignancy, was correlated with the cytological findings. Routine cytology revealed malignancy in 60% of effusions. Using FISH, aneuploid cell populations could be observed in 94% of cytologically positive and in 48% of cytologically negative effusions, thus reverting diagnosis to malignancy. To confirm malignancy in cases with a low frequency of aneuploid cells, two-colour FISH was additionally performed and indeed showed heterogeneous chromosomal aneuploidy within single nuclei. We conclude that FISH is a valuable tool in the diagnosis of malignancy and may serve as an adjunct to routine cytological examination, as demonstrated here for breast cancer effusions.

Involvement of P-glycoprotein in the transmembrane transport of interleukin-2 (IL-2), IL-4, and interferon-gamma in normal human T lymphocytes.

The physiological role of the multidrug resistance P-glycoprotein (P-gp), which is expressed by normal human T lymphocytes, is still largely unknown. To investigate whether or not P-gp is involved in the transport of cytokines, peripheral blood lymphocytes were stimulated with phytohemagglutinin (PHA) in the absence or presence of P-gp inhibitors, and concentrations of cytokines (interleukin-2 [IL-2], IL-4, IL-6, interferon-gamma [IFN-gamma]) in the supernatants of these cultures were quantitated by enzyme-linked immunosorbent assay. P-gp inhibitors included verapamil (Ver), tamoxifen (Tmx), and the P-gp specific monoclonal antibody UIC2. Release of IL-2 was significantly suppressed by these inhibitors at concentrations that were also effective in blocking efflux of Rhodamine-123 from normal T lymphocytes. IL-2 mRNA expression in lymphocytes was not different between PHA control and the cultures with P-gp inhibitors. Ver and Tmx did not interfere with T-cell activation as determined by CD25 and CD69 expression. In a nonhematological model, the P-gp expressing HCT-8 adenocarcinoma cell line, exogenously added IL-2 was shown to exert an inhibitory effect on P-gp mediated Rhodamine-123 efflux. In addition, transepithelial transport of IL-2 by electrophysiologically tight and polarized HCT-8 monolayers was examined. A time-dependent flux of IL-2 across dense monolayers, which was partially inhibited by Ver, was observed. We also investigated whether or not P-gp inhibitors suppressed release of other cytokines produced by activated T cells (IL-4, IL-6, IFN-gamma). Release of IL-4 and IFN-gamma was significantly inhibited by Ver, Tmx, and UIC2; however, release of IL-6 remained unaffected. These data show P-gp mediated transmembrane flux of IL-2 in T lymphocytes and HCT-8 cells. We conclude that P-gp participates in the transport of cytokines (IL-2, IL-4, and IFN-gamma) in normal peripheral T lymphocytes.

Interphase fluorescence in situ hybridization identifies chromosomal abnormalities in plasma cells from patients with monoclonal gammopathy of undetermined significance.

Karyotypic studies in patients with monoclonal gammopathy of undetermined significance (MGUS) have been hampered by a low percentage of bone marrow plasma cells (BMPC), which are predominantly nonproliferating. By combining cytomorphology and interphase fluorescence in situ hybridization (FISH) we investigated whether or not chromosomal abnormalities occur in BMPC from patients with MGUS. Studying chromosomes 3, 7, 11, and 18, which we found to be frequently aneuploid by FISH in multiple myeloma (MM), we observed three hybridization signals for one of these chromosomes 3 were most common, occurring in 38.9% of patients, followed by gains of chromosomes 11 (25%), 7 (16.7%), and 18 (5.6%) Among BMPC, the frequency of aneuploid cells was 18.9% +/- 13.9% (mean +/- SD) for chromosome 3, 22.3% +/- 9.2% for chromosome 11, 23.2% +/- 22.0% for chromosome 7, and 6.1% +/- 2.3% for chromosome 18. In five patients, chromosomal abnormalities were shown to be restricted to BMPC expressing cytoplasmic immunoglobulins corresponding to the serum paraprotein. No gain of hybridization signals was observed in normal and reactive plasma cells. In one patient with MGUS, metaphase cytogenetics revealed one abnormal metaphase with 47, XY, +4, and trisomy 4 was also demonstrated in a subpopulation of BMPC by interphase FISH. FISH results from patients with MGUS and newly diagnosed MM at stage IA (n = 14) indicated that aberrations involving > or = 2 chromosomes occurred significantly more often in early stage MM (P < .01). With respect to clinical and laboratory features, MGUS patients with and without chromosomal abnormalities were indistinguishable. Our results indicate that MGUS already has the chromosomal characteristics of a plasma cell malignancy.

Multiple myeloma: high incidence of chromosomal aneuploidy as detected by interphase fluorescence in situ hybridization.

Because metaphase cytogenetic studies in multiple myeloma (MM) are hampered by a low proliferative activity of myeloma cells in vitro, interphase cytogenetics by means of fluorescence in situ hybridization (FISH) should improve the detection of chromosomal abnormalities in MM. We therefore investigated chromosomal aneuploidy in 36 patients with MM using interphase FISH and alpha-satellite DNA probes for chromosomes 1, 3, 7, 8, 11, 12, 16, 17, 18, and X. By FISH, myeloma cells from 32 patients (88.9%) were aneuploid for at least one of the chromosomes examined. In 24 patients (66%), aberrations of > or = 3 chromosomes were observed. Aneuploidy was predominantly characterized by a gain of chromosome numbers, with involvement of chromosomes 3, 7, and 11 occurring in > 50% of patients. Loss of a centromeric signal suggesting monosomy was most frequently observed for chromosomes 17 (22.2% of patients) and X (monosomic in 42.3% of female patients, but loss of chromosome X was never observed in males, P < 0.05). Dual-color FISH studies provided evidence for marked heterogeneity of aneuploid cells in 8 patients (22.8%). Occurrence of chromosomal aneuploidy was independent of stage and pretreatment status. Gain of chromosome 3 was significantly correlated with an IgA paraprotein (P < 0.05). In 12 patients, the direct comparison of metaphase cytogenetics and FISH showed that FISH detected aneuploidy of chromosomes in 9 patients that was missed by metaphase analysis. In conclusion, interphase FISH, by which chromosomal aneuploidy was detected in almost 90% of patients with MM, represents an approach for evaluating the clinical significance of specific chromosomal abnormalities in MM.

Peripheral blood lymphocyte subsets and survival in small-cell lung cancer.

Measurement of lymphocyte subsets in peripheral blood is likely to reflect immune response of patients and therefore may be linked to survival in small-cell lung cancer (SCLC). Forty patients with SCLC (14 with limited and 26 with extensive disease at study entry) were included and followed for up to 23 months. Peripheral blood lymphocytes were determined by flow cytometry and levels for total-, T-, B-, helper-, suppressor-, activated T-cells and natural killer cells established and the T-helper-suppressor ratio (H-S ratio) calculated. Quartiles of lymphocyte subset cell counts at the start of follow-up and for the change over follow-up were investigated. Cox regression models indicated that H-S ratio was a significant predictor (p = 0.02) of survival. The risk ratio, after adjustment for competing risk factors, sex, age and stage of disease, was found to be 0.66 (95 percent confidence intervals, 0.46 to 0.95) and predicted that for each quartile of greater H-S ratio, the risk of death decreased by 34 percent. For change in cell counts over follow-up, total lymphocytes (p = 0.02) demonstrated a significant association with survival. Although our observation is limited by the fact that 13 patients were unavailable for follow-up, we conclude that H-S ratio can serve as an easily accessible marker of immune function and possible prognostic value in SCLC.