A potential probe set of fluorescence in situ hybridization for detection of lung cancer in bronchial brushing specimens

Abstract

Purpose: The study aims to find candidate probes of fluorescence in situ hybridization (FISH) for detection of lung cancer with bronchial brushings and to evaluate whether the accuracy of diagnosing lung cancer by cytological deviant and genetic abnormalities is greater than that of cytology alone.

Methods: Centromeric enumeration probes (CEPs) for chromosomes 2, 3, 6, 7, 8, 9, 11, 12, and 17 were analyzed using FISH in 74 surgical resection tissues, 32 operative margin tissues without tumor involvement of lung cancer, and 174 bronchial brushings.

Results: The aneuploidy rates of the tested probes were 61.7, 89.1, 80.0, 92.7, 65.0, 70.4, 66.7, 71.8, 68.9 % in tumor tissues, and 29.3, 58.9, 33.3, 69.6, 67.0, 40.3, 38.0, 49.3, 35.1 % in bronchial brushings. The combination of cytology and FISH using the three-probe set for chromosomes 3+7+8 significantly improved the sensitivity of bronchial brushing examination for lung cancer detection (P = 0.00003), especially squamous cell carcinoma (SCC), which increased from 78.0 to 98.2 %. The specificity of the 3+7+8 probe set was 94.6 %. Moreover, a high aneuploidy rate of the probe set in bronchial brushings was detected more often in SCCs (P = 0.029) and late-stage non-small-cell lung cancer (NSCLC) (P = 0.044). Kaplan-Meier curves indicated that adenocarcinoma (ADC) patients with high aneuploidy rate of CEP3 in tissue samples exhibited poorer overall survival (P = 0.016).

Conclusions: FISH performed on cytology preparations is useful for confirmation of cancer diagnosis. The three-probe set, 3+7+8, has potential value for the detection of SCCs in bronchial brushings.

Fig. 1

ROC curves for CEP 2, 3, 6, 7, 8, 9, 11, 12, and 17 in 74 NSCLC tumor tissues and 32 surgical margin tissues. The determined cut-off values were 35.3, 14.6, 19.3, 11.7, 13.9, 20.2, 20.7, 17.1, and 21.2 % for CEP 2 (a), 3 (b), 6 (c), 7 (d), 8 (e), 9 (f), 11 (g), 12 (h), and 17 (i), respectively

Fig. 2

Representative cases with trisomy, tetrasomy, and polysomy using different probes in bronchial brushings and tumor tissues. a Trisomy for CEP7 (1) and CEP8 (2) in bronchial brushing specimens and CEP9 (3) and CEP17 (4) in tumor tissues. b Tetrasomy for CEP7 (1), CEP8 (2), and CEP12 (3) in bronchial brushing specimens and CEP2 (4), CEP6 (5), and CEP11 (6) in tumor tissues. c Polysomy for CEP7 (1) and CEP12 (2) in bronchial brushings specimens and CEP2 (3), CEP6 (4), CEP9 (5), and CEP17 (6) in tumor tissues. d Aneuploidies detected by Multitarget FISH. 1 CEP7 (Red) and CEP3 (Green); 2. CEP12 (Red) and CEP8 (Green); 3. CEP8 (Red) and CEP17 (Green); 4. CEP12 (Red), CEP11 (Yellow) and CEP7 (Green). FISH analyses (1) and (2) were performed in bronchial brushing specimens; 3 and 4 were performed in tumor tissues

Fig. 3

Relationship between the aneuploidy rate of CEP3 in tissue samples and overall survival of ADC patients. Kaplan–Meier curves showing that ADC patients with high aneuploidy rate of CEP3 had a poorer OS compared to those with low aneuploidy rate of the probe (P = 0.016)