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:Neuroblastoma (NB) is an aggressive tumor that affects both infants and children. The disease outcome is greatly influenced by age of patient, stage, chromosome copy number aberrations (CNAs) and gene expression abnormalities. We analyzed, by microarray technology, genome and transcriptome of 3 groups of tumors of patients with metastatic disease: G1, stage 4S and MYCN single copy; G2, stage 4 younger than 18 months of age, MYCN single copy with no disease progression and G3, stage 4, older than 19 months, with unfavorable outcome. We found an accumulation of structural copy number aberrations (CNAs) in G3 whereas G1 tumors had mostly numerical (N) CNAs and G2 showed an intermediate behavior. Pair wise comparisons demonstrated that the average of N CNAs significantly decreased from G1 to G2 to G3 (9.6 G1 < 7.2 G2 < 3.6 G3); in contrast S CNAs significantly increased in G3 (0.7 G1 < 3.7 G2 < 7.0 G3). Interestingly, we observed several intra-chromosomal rearrangements in G3 tumors on chromosomes not usually involved in NB. Excluding MYCN amplified tumors by G3 we found a high frequency of S CNAs in this group. Gene expression analysis showed a deregulation of downstream genes of Ras and Rho signaling pathway among the 3 groups. It has been also observed a progressive switch off of development and adhesion genes and a switch on of cell cycle genes from G1 to G2 to G3. Moreover, the telemorase genes were significantly expressed in G3 with respect to remaining groups. Present data show an accumulation of S CNAs from stage 4S to 4. The deregulation of genes Rho/Ras pathway may explain the increase of tumor aggressiveness from G1 to G2 to G3. The increase of cell cycle and telomerase genes expression associated with G3 would provide unlimited replicative potential for these tumors and may be responsible for accumulation of S CNAs. Finally, we can argue that accumulation of structural aberrations and gene deregulation is age-dependent and it is associated with a more aggressive tumor phenotype. We analyzed 133 samples of metastatic neuroblastoma from patients divided into three groups: G1 49 patients stage 4S and MYCN single copy; G2 37 patients stage 4 younger than 18 months of age at diagnosis, MYCN single copy with no disease progression; G3 47 patients stage 4 older than 19 months of age at diagnosis, with unfavorable outcome.

Project description:Four unrelated families with the same unbalanced translocation der(4)t(4;11)(p16.2;p15.4) were identified. Both of the breakpoint regions in 4p16.2 and 11p15.4 were narrowed to large ~359-kb and ~215-kb low-copy repeat (LCR) clusters, respectively, by aCGH and SNP array analyses. DNA sequencing enabled mapping the breakpoints of one translocation to 24-bp within interchromosomal paralogous LCRs of ~130-kb in length and 94.7% DNA sequence identity located in olfactory receptor gene clusters, indicating nonallelic homologous recombination (NAHR) as the mechanism for translocation. To investigate the potential involvement of interchromosomal LCRs in recurrent chromosomal translocation formation, we performed computational genome-wide analyses and identified 5292 interchromosomal LCR substrate pairs, > 5-kb in size and sharing > 94% sequence identity that can potentially mediate chromosomal translocations. Additional proof for interchromosomal NAHR mediated translocation formation was provided by sequencing the breakpoints of another recurrent translocation, der(8)t(8;12)(p23.1;p13.31). The NAHR sites were mapped within 55-bp in ~7.8-kb paralogous subunits of 95.3% sequence identity located in the ~579-kb (chr8) and ~287-kb (chr12) LCR clusters. We demonstrate that NAHR mediates recurrent constitutional translocations throughout the human genome and provide a computationally determined genome-wide “recurrent translocation map”. Affymetrix Genome-Wide SNP Array 6.0 arrays (Affymetrix, Santa Clara, California) were employed to define the breakpoints on chromosomes 4, 8, 11, and 12. Analysis was performed according to the Genome-Wide Human SNP Nsp/Sty Assay Kit 5.0/6.0 protocol provided by the supplier. The arrays were scanned using a GeneChip® Scanner 3000 7G (Affymetrix, Inc.) and results were analyzed using Genotyping Console version 2.1 software. patient 1: Version 5 BAC array contained 853 BAC/PAC clones designed to cover genomic regions of 75 known genomic disorders, all 41 subtelomeric regions, and 43 pericentromeric regions. For each patient sample, two experiments were performed with reversal of the dye labels for the control and test samples. patient 2: Version 5.1 BAC array contained 853 BAC/PAC clones designed to cover genomic regions of 75 known genomic disorders, all 41 subtelomeric regions, and 43 pericentromeric regions. For each patient sample, two experiments were performed with reversal of the dye labels for the control and test samples. patient 3: The BAC emulated Version 6.1 OLIGO array was comprised of approximately 42,460 oligonucleotides representing 1400 BAC clones, covering ~150 genomic disorders, all 41 subtelomeric regions up to 12 Mb and 43 pericentromeric regions with backbone coverage of every chromosome at the 650-band level of cytogenetic resolution (http://www.bcm.edu/geneticlabs/cma/tables.html). The 42.46K oligonucleotides (oligos) were selected from initial testing of 105,000 oligos derived from the Agilent eArray library with strict selection criteria and removal of repetitive sequences to ensure optimal performance with greater dynamic range. This targeted 42.46 K OLIGO array (V6 OLIGO) corresponds to genomic regions covered by the V6 BAC arrays and was manufactured in a 4 x 44K format with an average of 28-30 oligos per region previously covered by a single BAC clone. patient 5: The BAC emulated Version 6.3 OLIGO array was comprised of approximately 43,580 oligonucleotides representing 1400 BAC clones, covering ~150 genomic disorders, all 41 subtelomeric regions up to 12 Mb and 43 pericentromeric regions with backbone coverage of every chromosome at the 650-band level of cytogenetic resolution (http://www.bcm.edu/geneticlabs/cma/tables.html). This targeted OLIGO array corresponds to genomic regions covered by the V6 BAC arrays and was manufactured in a 4 x 44K format with an average of 28-30 oligos per region previously covered by a single BAC clone. patient 6: The BAC emulated Version 6.4 OLIGO array was comprised of approximately 43,700 oligonucleotides representing 1400 BAC clones, covering ~150 genomic disorders, all 41 subtelomeric regions up to 12 Mb and 43 pericentromeric regions with backbone coverage of every chromosome at the 650-band level of cytogenetic resolution (http://www.bcm.edu/geneticlabs/cma/tables.html). This targeted OLIGO array corresponds to genomic regions covered by the V6 BAC arrays and was manufactured in a 4 x 44K format with an average of 28-30 oligos per region previously covered by a single BAC clone. Patient 4 was a known t(4;11) translocation patient form previous report and only ran on Affymetrix array.

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%.

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