Dataset Information

Genomic aberrations in normal appearing mucosa fields distal from oral potentially malignant lesions.

ABSTRACT:

Objectives

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.

Methods

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).

Results

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).

Conclusions

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.

SUBMITTER: Giaretti W

PROVIDER: S-EPMC3268978 | biostudies-literature | 2012 Feb

REPOSITORIES: biostudies-literature

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Publications

Genomic aberrations in normal appearing mucosa fields distal from oral potentially malignant lesions.

Giaretti W W Maffei M M Pentenero M M Scaruffi P P Donadini A A Di Nallo E E Malacarne D D Marino R R Familiari U U Coco S S Tonini G P GP Castagnola P P Gandolfo S S

Cellular oncology (Dordrecht, Netherlands) 20111206 1

<h4>Objectives</h4>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 associat ...[more]

PMID: 22144094

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Project description:The aim of the study was to address the concept of field cancerization in oral cancer. The presence of genomic aberrations, indicative of chromosomal instability (CIN), in oral distant fields (ODFs) of visually normal and non-dysplastic mucosa at the mirror image from concomitant oral potentially malignant lesions (OPMLs) was investigated. This pilot study comprised 16 OPMLs (8 without dysplasia, nd-OPMLs; 8 with dysplasia, d-OPMLs) and 16 ODFs. DNA diploid (DNA Index, DI=1) and aneuploid (DIM-bM-^IM- 1) sublines were detected by high resolution DNA-flow cytometry (FCM) at (hr DNA-FCM) using DAPI stained nuclei suspensions. Nuclei with different DIs were FCM-sorted in order to enrich the epithelial component and to obtain genomic DNA for high resolution oligonucleotide array-Comparative Genomic Hybridization (a-CGH) analysis to provide a genome-wide measurement of DNA copy number aberrations (CNAs). The frequencies of DNA aneuploidy in ODFs and OPMLs were 6.2% and 43.8%, respectively (p=0.037). ODFs and nd-OPMLs were all near-diploid (DIM-bM-^IM- 1 and DIM-bM-^IM-$1.4), while d-OPMLs were also high-aneuploid (DI>1.4). CNA averages were 2.3 in ODFs (1.5 for nd-OPMLs and 3.1 for d-OPMLs), and 7.325 in OPMLs (3.0 in nd-OPMLs; 11.6 in d-OPMLs). CNAs were present in the DNA diploid sublines and often the same CNAs were observed in both ODFs and corresponding OPMLs DNA aneuploid sublines and CNAs in the present series of 16 ODFs are likely to represent early events of the natural history of oral carcinogenesis and to indicate an early onset of the field effect cancerization. Moreover, gains within 20q13.33-qter, 7p22.2-pter and 16p13.3-pter chromosomal regions in ODFs and in the relative OPMLs suggest that specific genes localized in these regions (RTEL1, MAD1L1 and TEL2) might contribute to the ODF/d-OPML transition. We analyzed: 8 samples of oral potentially malignant lesions with dysplasia, 8 samples of oral potentially malignant lesions without dysplasia and for each patient a corresponding oral distant field of visually normal mucosa.

Project description:The mucosae of the oral cavity are different at the histological level but are all exposed to common genotoxic agents. As a result of this exposure, changes in the mucosal epithelia develop giving rise to Oral Potentially Malignant Lesions (OPMLs), which with time may in turn progress to Oral Squamous Cell Carcinomas (OSCCs). Therefore, much effort should be devoted to identify features able to predict the likeliness of progression associated with an OPML. Such features may be helpful in assisting the clinician to establish both appropriate therapies and follow-up schedules. Here, we report a pilot study that compared the anatomical subsites of OPMLs development with occurrence of DNA aneuploidy and chromosomal copy number aberrations (CNAs). Multiple samples from histologically diagnosed OPMLs were processed for high resolution DNA flow cytometry (hr DNA-FCM) in order to determine the relative DNA content expressed by the DNA index (DI). Additionally, array-Comparative Genomic Hybridization (a-CGH) analysis was performed on FCM-sorted nuclei subpopulations based on DI values. Tongue OPMLs were more frequently associated with DNA aneuploidy and CNAs than OPMLs arising from all the other mucosal subsites. We suggest that the follow-up and the management of the patients with tongue OPMLs should receive a distinctive special attention. Clearly, this conclusion should be validated in a prospective clinical study. exposed to common genotoxic agents. As a result of this exposure, changes in the mucosal epithelia develop giving rise to Oral Potentially Malignant Lesions (OPMLs), which with time may in turn progress to Oral Squamous Cell Carcinomas (OSCCs). Therefore, much effort should be devoted to identify features able to predict the likeliness of progression associated with an OPML. Such features may be helpful in assisting the clinician to establish both appropriate therapies and follow-up schedules. Here, we report a pilot study that compared the anatomical subsites of OPMLs development with occurrence of DNA aneuploidy and chromosomal copy number aberrations (CNAs). Multiple samples from histologically diagnosed OPMLs were processed for high resolution DNA flow cytometry (hr DNA-FCM) in order to determine the relative DNA content expressed by the DNA index (DI). Additionally, array-Comparative Genomic Hybridization (a-CGH) analysis was performed on FCM-sorted nuclei subpopulations based on DI values. Tongue OPMLs were more frequently associated with DNA aneuploidy and CNAs than OPMLs arising from all the other mucosal subsites. We suggest that the follow-up and the management of the patients with tongue OPMLs should receive a distinctive special attention. Clearly, this conclusion should be validated in a prospective clinical study. We analyzed: 19 samples (4 aneuploid and 15 diploid components) deriving from oral potentially malignant lesions without dysplasia obtained of 16 patients; 14 samples (2 aneuploid and 12 diploid components) deriving from oral potentially malignant lesions with dysplasia obtained from 11 patients (two patients had multiple dysplastic lesions); 2 samples from visually normal mucosa in the near field obtained from two patients with dysplastic lesions. All the aneuploid samples had a purity of at least 90%.

Dataset Information

Genomic aberrations in normal appearing mucosa fields distal from oral potentially malignant lesions.

Objectives

Methods

Results

Conclusions

Publications

Genomic aberrations in normal appearing mucosa fields distal from oral potentially malignant lesions.

Similar Datasets

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