To Örebro University

Chromosomal instability (CIN), impaired telomere biology, and aberrant DNA methylation are implicated in colorectal cancer (CRC) development. Tracking these alterations from precancerous lesions through tumours to metastases may reveal biomarkers of CRC initiation and progression. Tissue samples from 44 patients with either high-grade colorectal dysplasia (HGA; n = 13) or advanced metastatic CRC (n = 31) were analyzed. CIN was assessed in all patients using either low-coverage whole-exome sequencing or microarray-based comparative genomic hybridization. In a subset of patients, genome-wide CpG methylation profiling (n = 19) and telomere length measurements (n = 15) were performed. CIN was detected in 85% of HGA patients, spanning focal CNVs in MALAT1 (46%) to recurrent alterations on chromosomes 11, 13, and 20, with PTK6 being the most frequently amplified (61%). CIN was comparable between primary tumours and synchronous metastases but was significantly elevated in metachronous cases. DEK was amplified in all metastases but the aberration was absent in primaries, irrespective of tissue chronicity. Methylation profiling distinguished HGA from adjacent non-dysplastic mucosa (9,859 differentially methylated CpGs) and unrelated tumour tissues (17,638 CpGs), whereas primary tumours and metastases differed at only five CpG sites. Both primary tumours and metastases appeared epigenetically younger than colonic mucosa. Metastases exhibited significantly shorter telomeres than both primary tumours (p = 0.019) and colonic mucosa (p = 0.001). The amplification of PTK6 may serve as an early biomarker detectable at the HGA stage, while DEK amplification appears crucial for metastatic progression and may represent a therapeutic target. Further validation is needed.

Vulvar cancer is a rare gynaecological disease that can be caused by infection with human papillomavirus (HPV). The mutational frequencies and landscape for HPV-associated and HPV-independent vulvar tumor development are supposedly two distinctly different pathways and more detailed knowledge on target biological mechanisms for individualized future treatments is needed. The study included formalin-fixed paraffin-embedded (FFPE) samples from 32 cancer patients (16 HPV-negative and 16 HPV-associated), treated in Örebro, Sweden from 1988 to 2008. The Oncomine™ Comprehensive Assay v3 was used to detect variants across 161 different tumor relevant genes. Data analysis included quality assessment followed by variant analysis of DNA with the Oncomine Comprehensive v3 workflow and with a custom filter using the VarSome Clinical software. The RNA-analysis was performed with the Oncomine Comprehensive v3 workflow. Totally, 94% of DNA libraries and 81% of RNA libraries were of adequate quality for further downstream analysis. With the Oncomine™ filter chain there was an increased number of variants in the HPV-negative group (2.5 variants) compared to the HPV-associated group (1.5 variants). Using custom filter and the Varsome Clinical software; additional single nucleotide variants (SNV) were detected where the vast majority were classified as likely benign/benign. HPV-negative tumors had a larger fraction of variants of unknown significance (VUS), and likely pathogenic/pathogenic compared to the HPV-associated tumours. The top 10 frequently mutated genes in HPV-indepentent tumors were TP53, POLE, PTCH1, BRCA2, CREBBP, NOTCH2, ARID1A, CDKN2A, MSH2, and NOTCH1. Three fusion genes were detected; TBL1XR1(1)::PIK3CA(2) (n = 2) and NF1(5)::PSMD11(2) (n = 1). Copy number variations (CNV) were more common in HPV-associated tumors (n = 13/16, 81%) compared to HPV-negative tumors (n = 9/14, 64%). The most frequent CNV was found in the cMYC gene, followed by CDK2 (n = 5) and CDK4 (n = 4). The main outcome of this study show that vulvar cancer harbour genetic variations of different types and specifically, HPV-independent tumours are molecularly very heterogeneous and harboured more SNVs while HPV-associated tumors more frequently presented with gene amplifications. The PI3K/AKT/mTOR1 pathway was affected in both the groups as well as the cell cycle regulation pathway. Similarly, the DNA repair gene POLE was found mutated in both vulvar cancer groups.

Microsatellite instability is characterised by gains or losses of nucleotides in short tandem repeat sequences, microsatellites, dispersed throughout the human genome. Microsatellite instability status is a molecular fingerprint for DNA mismatch repair deficiency. Clinical detection of microsatellite instability status is important for identifying inherited disease in patients with colorectal and endometrial cancer but has also a prognostic value for survival and prediction of treatment response. Lately, microsatellite instability has been used as a tumor agnostic biomarker that predicts response to immune checkpoint inhibitors. To identify microsatellite instability status clinically, PCR and immunohistochemistry have been the gold standard. On the contrary, next generation sequencing provide simultaneous accession of large number of microsatellite loci and can be combined with detection of several other biomarkers. 

The national collaboration Genome Medicine Sweden have developed a solid tumour gene panel composed of 560 cancer associated genes with integrated microsatellite instability score. Our aim was to validate the microsatellite instability status based on microsatellite instability score from GMS560 DNA panel against the clinically used methods. Extracted DNA (100 ng) from formalin fixed paraffin embedded tissue sections with various tumour cell content >10% were analysed. During target enrichment sequencing analysis, allelic distribution from 5000 microsatellite markers were calculated by MSIsensor Pro to generate an instability score. 

The cohort consisted of microsatellite instable verified colorectal cancer samples (n=20), microsatellite stable solid tumour material (n=60). Preliminary results generated a microsatellite instability score for the colorectal cancer samples with a mean of 26.5 % (CI: 23.4-29.6, range: 16.9-32.3). Microsatellite stable tumour samples had a mean microsatellite instability score of 1.5 % (CI: 0.93-2.07, range: 1-4.45). 

In conclusion, we found the microsatellite instability score from GMS560 DNA panel to be both diagnostically sensitive and specific for determining MSI status due to obvious separation in instability. 

Objective: In Sweden, endometrial carcinoma is number five among female cancers, with 1,400 new cases per year. The diagnostic and prognostic markers for the high-risk subgroups with unfavorable prognosis are under intense debate worldwide. The aim of the present study was to address the epigenetic differences in a consecutive series of endometrial carcinomas comprising a low-risk group (FIGO-grade 1) and a high-risk group (FIGO-grade 3) with highly significant different treatment outcomes and survival rates.

Method: We used the Illumina Infinium HumanMethylation450 BeadChip to analyze the DNA methylation pattern and investigated its association with clinicopathological features important for defining the high-risk (FIGO-grade 3) and low-risk (FIGO-grade 1) groups of patients with endometrial cancer.

Results: We identified 2,224 differentially methylated CpG sites. Gene ontology analysis classified the hypomethylated genes in the high-risk group were to cell adhesion and membrane, and the hypomethylated genes to cell adhesion. Increasing methylation level in FIGO-grade 3 cancers was significantly (P < 0.01) associated with advanced tumor stage for CpG sites located in the TBX2, CHST11, LRP5, and CIZ1/ DNM1 genes.

Conclusion: Our study identified specific DNA methylation signature in low-risk and high-risk endometrial tumors, and potential molecular biomarker genes associated with unfavorable clinical predictive and prognostic factors.

A child, 2 years with the "hypercalprotectinemia with hyperzincemia" clinical syndrome presented with atypical symptoms and signs, notably persistent fever of around 38°C, thrombocythaemia of >700 x 10(9) /L, and a predominance of persistent intestinal symptoms. In an effort to find a cure by identifying the dysregulated pathways we analyzed whole-genome mRNA expression by the Affymetrix HG U133 PLUS 2.0 array on three occasions 3 to 5 months apart. Major upregulation was demonstrated for the JAK/STAT pathway including in particular CD177, S100A8, S100A9, and S100A12, accounting for the thrombocytosis; a large number of interleukins, their receptors, and activators, accounting for the febrile apathic state; and the HMBG1 gene, possibly accounting for part of the intestinal symptoms. These results show that gene expression array technology may assist the clinician in the diagnostic workup of individual patients with suspected syndromal states of unknown origin, and the expression data can guide the selection of optimal treatment directed at the identified target pathways.

Endometrial carcinoma is one of the most frequent gynecological malignancies of the female. The diagnostic and prognostic markers for the high-risk subgroups with unfavorable prognosis are under intense debate worldwide, and, therefore, the aim of this study was to identify new potential DNA methylation markers for the high-risk groups. We used the Illumina Infinium HumanMethylation450 BeadChip to analyze the DNA methylation pattern and investigated its association with clinicopathological features important for defining the high-risk (FIGO-grade 3) and low-risk (FIGO-grade 1) groups of patients with endometrial cancer (n = 31 and n = 39, respectively). We identified specific DNA methylation signature in high-risk endometrial tumors, and potential molecular biomarker genes (TBX2, CHST11, and NID2) associated with unfavorable clinical predictive and prognostic factors.

Aim: The aim of the present study is to address a genome-wide search for novel methylation biomarkers in the rectal cancer (RC), as only scarce information on methylation profile is available.

Materials and methods: We analyzed methylation status in 25 pairs of RC and adjacent healthy mucosa using the Illumina Human Methylation 450 BeadChip.

Results: We found significantly aberrant methylation in 33 genes. After validation of our results by pyrosequencing, we found a good agreement with our findings. The BPIL3 and HBBP1 genes resulted hypomethylated in RC, whereas TIFPI2, ADHFE1, FLI1 and TLX1 were hypermethylated. An external validation by TCGA datasets confirmed the results.

Conclusion: Our study, with external validation, has demonstrated the feasibility of using specific methylated DNA signatures for developing biomarkers in RC.

Folate has a central role in the cell metabolism. This study aims to explore the DNA methylation pattern of the folate transporter genes FOLR1, PCFT, and RFC1 as well as the corresponding protein expressions in colorectal cancer (CRC) tissue and adjacent non-cancerous mucosa (ANCM). Our results showed statistically significant differences in the DNA-methylated fraction of all three genes at several gene regions; we identified three differentially methylated CpG sites in the FOLR1 gene, five CpG sites in the PCFT gene, and six CpG sites in the RFC1 gene. There was a pronounced expression of the FR alpha and RFC proteins in both the CRC and ANCM tissues, though the expression was attenuated in cancer compared to the paired ANCM tissues. The PCFT protein was undetectable or expressed at a very low level in both tissue types. Higher methylated fractions of the CpG sites 3-5 in the RFC1 gene were associated with a lower protein expression, suggestive of epigenetic regulation by DNA methylation of the RFC1 gene in the colorectal cancer. Our results did not show any association between the RFC and FR alpha protein expression and tumor stage, TNM classification, or tumor location. In conclusion, this is the first study to simultaneously evaluate both DNA methylation and protein expression of all three folate transporter genes, FOLR1, PCFT, and RFC1, in colorectal cancer. The results encourage further investigation into the possible prognostic implications of folate transporter expression and DNA methylation.

Aim: The onset and progression of colorectal cancer (CRC) involves a cascade of genetic and/or epigenetic events. The aim of the present study was to address the DNA methylation status of genes relevant in colorectal carcinogenesis and its progression, such as genes frequently mutated in CRC, genes involved in the DNA repair and Wnt signaling pathway.

Material & methods: We analyzed methylation status in totally 160 genes in 12 paired colorectal tumors and adjacent healthy mucosal tissues using the Illumina Infinium Human Methylation 450 BeadChip.

Results: We found significantly aberrant methylation in 23 genes (NEIL1, NEIL3, DCLRE1C, NHEJ1, GTF2H5, CCNH, CTNNB1, DKK2, DKK3, FZD5 LRP5, TLE3, WNT2, WNT3A, WNT6, TCF7L1, CASP8, EDNRB1, GPC6, KIAA1804, MYO1B, SMAD2 and TTN). External validation by mRNA expression showed a good agreement between hypermethylation in cancer and down-regulated mRNA expression of the genes EDNRB1, GPC6 and SMAD2, and between hypomethylation and up-regulated mRNA expression of the CASP8 and DCLRE1C genes.

Conclusion: Aberrant methylation of the DCLRE1C and GPC6 genes are presented here for the first time and are therefore of special interest for further validation as novel candidate biomarker genes in CRC, and merit further validation with specific assays.