Department of Diagnostic Oncology, Biophysics and Cytometry, National Institute for Cancer Research, Genoa, GE, Italy.
Cell Oncol (Dordr). 2012 Feb;35(1):43-52. doi: 10.1007/s13402-011-0064-2. Epub 2011 Dec 6.
Oral fields of visually normal and non-dysplastic mucosa (ODFs) may represent the precursors of oral potentially malignant lesions (OPMLs). Aim of the study was to provide new evidence for the concept of the "field carcinogenesis" model by comparing the ODF and OPML genomic aberration profiles obtained by high resolution DNA flow cytometry (hr DNA-FCM) and array-Comparative Genomic Hybridization (a-CGH). A second aim was to investigate if specific CGH aberrations were associated with DNA aneuploidy.
Nineteen patients with single OPMLs were recruited for the study. In parallel with obtaining samples of OPML tissue from 11 leukoplakias without dysplasia (nd-OPMLs) and 8 with dysplasia (d-OPMLs), we also obtained samples from distant ODFs. DNA aneuploid nuclei detected by hr DNA-FCM were physically separated, based on DNA content, from the DNA diploid components with a DNA-FCM-Sorter. These relatively pure subpopulations of epithelial nuclei were then submitted to DNA extraction and a-CGH for a genome-wide analysis of DNA copy number aberrations (CNAs).
The frequencies of DNA aneuploidy (DI ≠ 1) among ODFs and OPMLs were respectively 5.3% and 32%. The DI aneuploid values of ODFs and nd-OPMLs were all near-diploid (DI ≠ 1 and DI ≤ 1.4), while for d-OPMLs were high-aneuploid (DI > 1.4) in 40% of the cases. CNA averages were 1.9 in ODFs and 6.5 in OPMLs. The gain of the chromosomal region 20q13.33-qter was observed in 37% of both ODFs and corresponding OPMLs. Additional common regions included 7p22.2-pter, 11p15.5-pter and 16p13.3-pter where gains were observed. Furthermore, gains of 20q13.31-q13.33 and of 5p13.33-pter and loss of 9p21.3 were detected at high frequency (respectively, at 62.5%, 50% and 50%) only in d-OPMLs. In particular, loss at 9p21.3, gain at 5p13.33-pter and gain of 20q13.31-q13.33 were associated with DNA aneuploidy (p = 0.00004; p = 0.0005; p = 0.01).
ODFs and OPMLs showed common CNAs in specific chromosomal regions suggesting that they may represent early events of the natural history of oral carcinogenesis according to the field effect cancerization and may contribute to the ODF-OPML transition. In addition, loss at 9p21.3 and gains at 5p13.33-pter and 20q13.31-q13.33 may contribute to DNA aneuploidization.
视觉正常且无发育不良的口腔黏膜（ODF）可能代表口腔潜在恶性病变（OPML）的前体。本研究旨在通过比较高分辨率 DNA 流式细胞术（hr DNA-FCM）和阵列比较基因组杂交（a-CGH）获得的 ODF 和 OPML 基因组畸变谱，为“场致癌”模型的概念提供新的证据。第二个目的是研究是否存在特定的 CGH 畸变与 DNA 非整倍体相关。
从 19 名患有单一 OPML 的患者中招募了 11 名无发育不良的角化病（nd-OPML）和 8 名有发育不良的角化病（d-OPML）的 OPML 组织。同时，我们还从远处的 ODF 中获取了样本。基于 DNA 含量，使用 hr DNA-FCM 分离出由 hr DNA-FCM 检测到的 DNA 非整倍体核，并用 DNA-FCM 分选器将其与 DNA 二倍体成分分离。然后，这些相对纯净的上皮核亚群被提交用于 DNA 提取和 a-CGH，以进行全基因组 DNA 拷贝数畸变（CNA）分析。
ODF 和 OPML 中的 DNA 非整倍体（DI≠1）频率分别为 5.3%和 32%。ODF 和 nd-OPML 的 DI 非整倍体值均接近二倍体（DI≠1 和 DI≤1.4），而 d-OPML 的 DI 非整倍体值在 40%的病例中较高（DI>1.4）。CNA 平均值分别为 ODF 的 1.9 和 OPML 的 6.5。在 37%的 ODF 和相应的 OPML 中观察到 20q13.33-qter 染色体区域的增益。其他常见区域包括 7p22.2-pter、11p15.5-pter 和 16p13.33-pter，其中观察到增益。此外，在 62.5%、50%和 50%的 d-OPML 中高频检测到 20q13.31-q13.33、5p13.33-pter 和 9p21.3 的丢失。特别是，9p21.3 的缺失、5p13.33-pter 的增益和 20q13.31-q13.33 的增益与 DNA 非整倍体相关（p=0.00004；p=0.0005；p=0.01）。
ODF 和 OPML 显示出特定染色体区域的共同 CNA，表明它们可能代表口腔癌发生自然史中的早期事件，符合场效应癌变，并可能有助于 ODF-OPML 转变。此外，9p21.3 的缺失和 5p13.33-pter 和 20q13.31-q13.33 的增益可能有助于 DNA 非整倍体化。
