Sawyer E J, Hanby A M, Ellis P, Lakhani S R, Ellis I O, Boyle S, Tomlinson I P
Molecular and Population Genetics Laboratory, Imperial Cancer Research Fund, London, UK.
Am J Pathol. 2000 Mar;156(3):1093-8. doi: 10.1016/S0002-9440(10)64977-2.
Phyllodes tumors are fibroepithelial mammary lesions that tend to behave in a benign fashion but may undergo sarcomatous transformation. A study of clonality in these tumors has suggested that the epithelial component is polyclonal, but the stroma is monoclonal, and thus forms the neoplastic component of the lesion. In this study microsatellites on chromosome 1q and chromosome 3p were assessed for allelic imbalance (AI) in 47 phyllodes tumors; in all cases stroma and epithelium were analyzed separately. Ten of 42 (24%) phyllodes tumors showed AI at one or more markers on 3p, and 14 of 46 (30%) showed AI on chromosome 1. Five tumors had changes in both the epithelium and stroma. Eight tumors had changes only detectable in the stroma and eight, changes in the epithelium only. Three tumors exhibited low-level microsatellite instability in the epithelium but not in the stroma. The results show that AI on 3p and 1q does occur in phyllodes tumors and that it can occur in both the stroma and epithelium, sometimes as independent genetic events. These unexpected findings throw into doubt the classical view that phyllodes tumors are simply stromal neoplasms and raise questions about the nature of stromal and epithelial interactions in these tumors.
叶状肿瘤是一种纤维上皮性乳腺病变，通常表现为良性，但可能发生肉瘤样转化。一项关于这些肿瘤克隆性的研究表明，上皮成分是多克隆的，而间质是单克隆的，因此形成了病变的肿瘤成分。在本研究中，对47例叶状肿瘤的1号染色体和3号染色体上的微卫星进行了等位基因不平衡（AI）评估；所有病例均分别分析了间质和上皮。42例叶状肿瘤中有10例（24%）在3号染色体上的一个或多个标记处显示AI，46例中有14例（30%）在1号染色体上显示AI。5例肿瘤的上皮和间质均有改变。8例肿瘤仅在间质中检测到改变，8例仅在上皮中有改变。3例肿瘤上皮表现出低水平微卫星不稳定，而间质未出现。结果表明，3号染色体和1号染色体上的AI在叶状肿瘤中确实存在，并且可同时出现在间质和上皮中，有时是独立的遗传事件。这些意外发现使叶状肿瘤仅仅是间质肿瘤这一传统观点受到质疑，并引发了关于这些肿瘤中间质与上皮相互作用本质的问题。
