Ith methylation data. The column “ CV-support” in the table indicates the percentage of the cross-validation training sets in which each gene was selected during “leave-one out cross validation”. 100 means that the gene is so strong that it was selected in all of the cross-validated training sets. “Geom. mean of intensities” is derived from chip intensity-values. doi:10.1371/journal.pone.0056609.tDiscussionThe presented study was conducted to investigate SNPs as well as hyper/hypomethylated genes in ten chordoma patients. The first part of the study focused on SNP analyses. We confirmedcopy number alterations known in chordomas and describe novel gains and losses. In accordance to Le et al. who HA15 web reported array comparative genomic hybridization (CGH) in 21 sporadic chordomas and found large copy number losses on chromosomes 1p, 3, 4, 9, 10, 13, 14, and 18, we were also able to demonstrateTable 4. Composition of the classifier derived from class prediction (sorted by t -value): For feature selection the “univariate pvalue ,0.05 and 2 fold -change between classes” was applied. The columnParametric p-value 1 2 3 4 5 6 7 8 9 0.0150536 0.0182198 0.0330808 0.0412258 0.0295713 0.0227937 0.0184278 0.0070848 5.53e-t-value 22.77 22.672 22.364 2.248 2.422 2.557 2.666 3.15 5.CV support 100 100 50 44 75 94 100 100Geom mean of intensities in chordoma 1398381572.97 6375978837.27 417345518.9 11770399604.19 5239084212.46 34359738368 152757376.44 26322102103.28 2047350879.Geom mean of intensities in blood 184247873471.87 34804904883.29 12040221110.61 406469246.17 240494470.75 2005658405.4 703546.19 1053729641.19 100421.Fold-change 0.0076 0.18 0.035 28.96 21.78 17.13 217.12 24.98 20387.Gene symbol C3 XIST TACSTD2 FMR1 HIC1 RARB DLEC1 KL RASSFThe column “ CV-support” in the table indicates the percentage of the cross-validation training sets in which each gene was selected during “leave-one out cross validation”. 100 means that the gene is so strong that it was selected in all of the cross-validated training sets. “Geom mean of intensities” is derived from transformed qPCR-Ct values. doi:10.1371/journal.pone.0056609.tDNA Methylation and SNP Analyses in Chordomacommon losses including chromosome 1, 4, 9, 10, 13, 14, 18, 20, and 22 as well as common gains in 7, 12, and 19. Interestingly, in 100 of our cases chromosome 3 (3p26.3-q29) was lost. These findings are also comparable with data previously reported by Hallor et al. and Le et al. [4,12]. Copy number gains/losses present in more than 50 of patients of well-known cancer associated genes for example CDKN2A, CDKN2B, RAF1 and PTEN were found and may play an important role in chordoma development. Overall, chromosome 3 shows the majority of genetic alterations. The common involvement of this chromosome has been already described in early studies by demonstrating a 3p loss [13,14] In addition losses on chromosome 3 relating PIK3CA and BCL6 were obtained. Currently there are several inhibitors of the PI3K (phosphatidylinositol 3-kinase) pathway under investigation in solid tumours [15]. Although cross talk of the PI3K pathway with other pathways in get Haloxon particular the RAS/RAF/MEK pathways have been reported, inhibition of the PI3K pathway could be an attractive therapeutic target and is definitely worth further investigations. BCL6 is a transcriptional repressor binding DNA through zinc fingers and regulates transcription through interacting with other factors like Jun proteins and histone deacety.Ith methylation data. The column “ CV-support” in the table indicates the percentage of the cross-validation training sets in which each gene was selected during “leave-one out cross validation”. 100 means that the gene is so strong that it was selected in all of the cross-validated training sets. “Geom. mean of intensities” is derived from chip intensity-values. doi:10.1371/journal.pone.0056609.tDiscussionThe presented study was conducted to investigate SNPs as well as hyper/hypomethylated genes in ten chordoma patients. The first part of the study focused on SNP analyses. We confirmedcopy number alterations known in chordomas and describe novel gains and losses. In accordance to Le et al. who reported array comparative genomic hybridization (CGH) in 21 sporadic chordomas and found large copy number losses on chromosomes 1p, 3, 4, 9, 10, 13, 14, and 18, we were also able to demonstrateTable 4. Composition of the classifier derived from class prediction (sorted by t -value): For feature selection the “univariate pvalue ,0.05 and 2 fold -change between classes” was applied. The columnParametric p-value 1 2 3 4 5 6 7 8 9 0.0150536 0.0182198 0.0330808 0.0412258 0.0295713 0.0227937 0.0184278 0.0070848 5.53e-t-value 22.77 22.672 22.364 2.248 2.422 2.557 2.666 3.15 5.CV support 100 100 50 44 75 94 100 100Geom mean of intensities in chordoma 1398381572.97 6375978837.27 417345518.9 11770399604.19 5239084212.46 34359738368 152757376.44 26322102103.28 2047350879.Geom mean of intensities in blood 184247873471.87 34804904883.29 12040221110.61 406469246.17 240494470.75 2005658405.4 703546.19 1053729641.19 100421.Fold-change 0.0076 0.18 0.035 28.96 21.78 17.13 217.12 24.98 20387.Gene symbol C3 XIST TACSTD2 FMR1 HIC1 RARB DLEC1 KL RASSFThe column “ CV-support” in the table indicates the percentage of the cross-validation training sets in which each gene was selected during “leave-one out cross validation”. 100 means that the gene is so strong that it was selected in all of the cross-validated training sets. “Geom mean of intensities” is derived from transformed qPCR-Ct values. doi:10.1371/journal.pone.0056609.tDNA Methylation and SNP Analyses in Chordomacommon losses including chromosome 1, 4, 9, 10, 13, 14, 18, 20, and 22 as well as common gains in 7, 12, and 19. Interestingly, in 100 of our cases chromosome 3 (3p26.3-q29) was lost. These findings are also comparable with data previously reported by Hallor et al. and Le et al. [4,12]. Copy number gains/losses present in more than 50 of patients of well-known cancer associated genes for example CDKN2A, CDKN2B, RAF1 and PTEN were found and may play an important role in chordoma development. Overall, chromosome 3 shows the majority of genetic alterations. The common involvement of this chromosome has been already described in early studies by demonstrating a 3p loss [13,14] In addition losses on chromosome 3 relating PIK3CA and BCL6 were obtained. Currently there are several inhibitors of the PI3K (phosphatidylinositol 3-kinase) pathway under investigation in solid tumours [15]. Although cross talk of the PI3K pathway with other pathways in particular the RAS/RAF/MEK pathways have been reported, inhibition of the PI3K pathway could be an attractive therapeutic target and is definitely worth further investigations. BCL6 is a transcriptional repressor binding DNA through zinc fingers and regulates transcription through interacting with other factors like Jun proteins and histone deacety.
