Institute for Pathology, University Hospital of Basel, Basel, Switzerland.
Cancer Cytopathol. 2011 Dec 25;119(6):404-10. doi: 10.1002/cncy.20171. Epub 2011 Jul 5.
Fluorescence in situ hybridization (FISH) is routinely used to help clarify atypical urinary cytology. However, to the authors' knowledge, little is known regarding the frequency of chromosomal aberrations in non-neoplastic conditions that could potentially lead to false-positive FISH results. The objective of the current study was to evaluate the frequency of chromosomal aberrations in benign cells of the urinary tract using the UroVysion FISH test.
The authors analyzed 77 Papanicolaou-stained benign urine cytology specimens with reactive epithelial atypia using a FISH assay detecting the chromosomes 3, 7, and 17 and the gene locus 9p21. A positive test result was defined as an increased copy number of at least 2 chromosomes in ≥ 4 of 25 cells, or > 10 cells with a tetraploid or octaploid pattern, or homozygous or heterozygous deletion of 9p21 (≥ 12cells).
FISH was positive in 27 of 77 bladder washings (35.1%) including 25 of 65 bladder washings (40.5%) and 2 of 15 voided urines (13.5%) from patients with irritative bladder (15 of 36 patients), a history of radiotherapy (7 of 12 patients), nonspecific cystitis (3 of 11 patients), hematuria (3 of 8 patients), and lithiasis (1 of 4 patients) . In 7 of 27 FISH-positive urothelial specimens, the positivity was solely due a polyploid pattern (tetraploid/octaploid pattern) in > 10 of the cells.
Chromosomal aberrations can occur in reactive urothelial cells, with a tetraploid pattern being the most common. Even an aneuploid pattern of FISH signals does not always prove malignancy because it rarely occurs in reactive urothelial cells. Correlation of FISH results with cytomorphology and patient history is crucial to avoid false-positive diagnoses.
荧光原位杂交（FISH）常用于帮助阐明非典型尿细胞学。然而，据作者所知，对于可能导致假阳性 FISH 结果的非肿瘤性病变中染色体异常的频率知之甚少。本研究的目的是使用 UroVysion FISH 试验评估尿路上皮良性细胞中染色体异常的频率。
作者使用检测染色体 3、7 和 17 以及基因座 9p21 的 FISH 检测分析了 77 例反应性上皮细胞异型性的巴氏染色良性尿细胞学标本。阳性检测结果定义为至少 2 条染色体在 25 个细胞中的 4 个或更多细胞中出现拷贝数增加，或 10 个细胞以上出现四倍体或八倍体模式，或 9p21 纯合或杂合缺失（≥ 12 个细胞）。
27 例膀胱冲洗液 FISH 阳性（35.1%），其中 25 例膀胱冲洗液（40.5%）来自刺激性膀胱（36 例患者中的 15 例），12 例患者中有 7 例放疗史，11 例患者中有 3 例非特异性膀胱炎，8 例患者中有 3 例血尿，4 例患者中有 1 例结石。在 27 例 FISH 阳性尿路上皮标本中，有 7 例仅因 > 10 个细胞中存在多倍体模式（四倍体/八倍体模式）而呈阳性。
染色体异常可发生在反应性尿路上皮细胞中，最常见的是四倍体模式。即使 FISH 信号的非整倍体模式也不一定证明恶性肿瘤，因为它很少发生在反应性尿路上皮细胞中。将 FISH 结果与细胞形态学和患者病史相关联对于避免假阳性诊断至关重要。
