Droplet digital PCR analysis of CDH13 methylation status in Slovak women with invasive ductal breast cancer.

Identifying novel epigenetic biomarkers is a promising way to improve the clinical management of patients with breast cancer. Our study aimed to determine the methylation pattern of 25 tumor suppressor genes (TSG) and select the best methylation biomarker associated with clinicopathological features in the cohort of Slovak patients diagnosed with invasive ductal carcinoma (IDC). Overall, 166 formalin-fixed, paraffin-embedded (FFPE) tissues obtained from patients with IDC were included in the study. The methylation status of the promoter regions of 25 TSG was analyzed using semiquantitative methylation-specific MLPA (MS-MLPA). We identified CDH13 as the most frequently methylated gene in our cohort of patients. Further analysis by ddPCR confirmed an increased level of methylation in the promoter region of CDH13. A significant difference in CDH13 methylation levels was observed between IDC molecular subtypes LUM A versus HER2 (P = 0.0116) and HER2 versus TNBC (P = 0.0234). In addition, significantly higher methylation was detected in HER2+ versus HER2- tumors (P = 0.0004) and PR- versus PR+ tumors (P = 0.0421). Our results provide evidence that alteration in CDH13 methylation is associated with clinicopathological features in the cohort of Slovak patients with IDC. In addition, using ddPCR as a methylation-sensitive method represents a promising approach characterized by higher precision and technical simplicity to measure the methylation of target CpGs in CDH13 compared to other conventional methods such as MS-MLPA.

Hypermethylated GRIA4, a potential biomarker for an early non-invasive detection of metastasis of clinically known colorectal cancer.

Introduction: Colorectal cancer (CRC) can develop through several dysregulated molecular pathways, including the serrated pathway, characterized by CpG island methylator (CIMP) phenotype. Although the tumor tissue is a commonly tested material, sample types such as stool or plasma, bring a new, non-invasive approach. Several cancer-related methylated genes have been identified in CRC patients, including gene GRIA4, showing promising diagnostic potential. The aim of our study was to develop a sensitive droplet digital PCR (ddPCR) assay to examine GRIA4 hypermethylation status in CRC patients and evaluate its diagnostic potential in tissue and liquid biopsy samples. Methods: In total, 23 patients participated in this study, 7 patients with primary CRC and 16 patients with liver metastasis of clinically known CRC. We obtained tumor and non-tumor tissues (N=17), blood samples pre- and post-surgery (N=22), and blood of five volunteers without a personal cancer history. We have developed and optimized a ddPCR assay for GRIA4 hypermethylation detection, from tissue and plasma samples. Results: We detected significantly increased GRIA4 methylation in tumor tissues compared to their adjacent non-tumor tissue, p<0.0001. Receiver operating characteristic (ROC) analysis defined cutoff values to separate primary tumors and metastases from non-tumor colon/rectum, specifically 36.85% for primary tumors and 34.81% for metastases. All primary tumors were above this threshold. When comparing the methylation levels of metastatic vs. non-tumor tissue, a smaller increase was observed in liver metastasis versus colon tissue (3.6× gain; p=0.001), then in liver metastasis versus adjacent liver tissue (17.4× gain; p<0.0001). On average, GRIA4 hypermethylation in primary tumor plasma was 2.8-fold higher (p=0.39), and in metastatic plasma, 16.4-fold higher (p=0.0011) compared to healthy individuals. Hypermethylation in metastatic plasma was on average 5.9 times higher (p=0.051) than in primary tumor plasma. After tumor removal surgery, average hypermethylation decrease in plasma was 1.6× for primary (p=0.037) and 4.5× for metastatic patients (p=0.023). Discussion: Based on our data, it can be inferred that GRIA4 serves as a tissue specific biomarker for the colon/rectum tissue, thus is suitable for cancer classification. This biomarker showed the potential to be an attractive target for early non-invasive detection of metastases of clinically known CRC, although additional analysis has to be performed.

Small-scale variants and large deletions in BRCA1/2 genes in Slovak high-grade serous ovarian cancer.

The role of PARP inhibitors is to prevent the polymerase from repairing the single-strand break that occurred due to tumor growth and thus induce cell apoptosis when the homologous recombination deficiency (HRD) system is disabled. The eliminated system can be monitored especially in patients with serous ovarian epithelial tumors. Current studies still show the highest progression-free survival (PFS) in the examined groups with BRCA mutant status, even though they are also effective in the case of a disrupted HRD system, apart from BRCA genes. The study cohort consists of women diagnosed with high-grade serous ovarian cancer (HGSOC), after at least two lines of chemotherapy and after relapse of the disease, as determined by ESMO standards and guidelines. The commercially available tool SOPHIA DDM™ (SophiaGenetics, Switzerland) was used to classify the variants after sequencing. The most common variants (pathogenic or likely pathogenic) were in BRCA1 c.1067 A>G (rs1799950) and c.5266dupC (rs80357906) and in BRCA2 c.9976 A>T (rs11571833). Large deletions were detected in one and three cases in the BRCA1 and BRCA2 genes, respectively. A mutation in the BRCA1/2 genes was confirmed in 50% of the examined patients. In the study, we focused on the identification of mutated BRCA genes by a commercially available Sophia DDM™ system to identify a pathogenic or probable pathogenic variant in a cohort of patients with HGSOC in the Slovak population, which could result in better management and stratification of the individual.

Interaction of cervical microbiome with epigenome of epithelial cells: Significance of inflammation to primary healthcare.

One pillar of the predictive, preventive, and personalized medicine framework strategies is the female health. The evaluation of women's lifestyle and dietary habits in context with genetic and modifiable risk factors may reflect the prevention of cervical cancer before the occurrence of clinical symptoms and prediction of cervical lesion behavior. The main aim of this review is to analyze publications in the field of precision medicine that allow the use of research knowledge of cervical microbiome, epigenetic modifications, and inflammation in potential application in clinical practice. Personalized approach in evaluating patient's risk of future development of cervical abnormality should consider the biomarkers of the local microenvironment characterized by the microbial composition, epigenetic pattern of cervical epithelium, and presence of chronic inflammation. Novel sequencing techniques enable a more detailed characterization of actual state in cervical epithelium. Better understanding of all changes in multiomics level enables a better assessment of disease prognosis and selects the eligible targeted therapy in personalized medicine. Restoring of healthy vaginal microflora and reversing the outbreak of cervical abnormality can be also achieved by dietary habits as well as uptake of prebiotics, probiotics, synbiotics, microbial transplantation, and others.

Detection of therapeutically relevant and concomitant rare somatic variants in colorectal cancer.

In colorectal cancer (CRC), clinically relevant biomarkers are known for genome-guided therapy that can be detected by both first and next generation methods. The aim of our work was to introduce a robust NGS assay that will be able to detect, in addition to standard predictive single nucleotide-based biomarkers, even rare and concomitant clinically relevant variants. Another aim was to identify truncating mutations in APC and pathogenic variants in TP53 to divide patients into potentially prognostic groups. A multigene panel with hotspots in 50 cancer-critical genes was used. Finally, 86 patients diagnosed with primary or metastatic colorectal cancer were enrolled. In total, there were identified 163 pathogenic variants, among them in the genes most recurrent mutated in CRC such as TP53 (49%), the RAS family genes KRAS and NRAS (47%), APC (43%), and PIK3CA (15%). In 30 samples, two driver mutations were present in one sample, 11 patients were without any mutations covered by this panel. In one patient, a novel variant in BRAF p.D594E was found, not previously seen in CRC, and was concomitant with KRAS p.G12A. In KRAS, a potentially sensitive mutation to anti-EGFR therapy p.A59T was found along with the PIK3CA missense variant p.E545K. It was possible to divide patients into groups based on the occurrence of truncating APC variant alone or concomitant with TP53 or KRAS. Our results demonstrate the potential of small multigene panels that can be used in diagnostics for the detection of rare therapeutically relevant variants. Moreover, the division of patients into groups based on the presence of APC and TP53 mutations enables this panel to be used in retrospective studies on the effectiveness of treatment with anti-EGFR inhibitors.

High-grade serous ovarian carcinoma and detection of inactivated BRCA genes from biopsy material of Slovak patients.

Ovarian cancer is the leading cause of mortality among all gynecological cancers in developed countries and its most common and most lethal type is the high-grade serous ovarian carcinoma (HGSC). At the molecular level, nearly half of all HGSCs exhibit ineffective homologous DNA recombination and disruption of DNA damage/repair pathway inactivation caused often by BRCA1 and BRCA2 gene mutation. Recently, the detection of BRCA1/2 mutations became important for personalized treatment of HGSC patients with the PARP-inhibitors in the defined clinical setting of relapse after positive adjuvant platinum-based chemotherapeutic response. Based on the selection of patients by regional oncologists, we attempted to verify the possibilities of BRCA1/2 mutation testing on archival formalin-fixed paraffin-embedded (FFPE) biopsy material from regional hospitals. In the study we used: a/ FFPE tumor resections of 97 patients sent to our laboratory, originally stored in archives of regional departments for a period of 1-3 years and retrieved on the principle to contain a maximum of non-necrotic tumor tissue, b/ next-generation sequencing (NGS) assay covering all known mutations in the BRCA1/2 genes on MiSeq (Illumina® platform), and c/ Sophia DDM® bioinformatics platform. After processing of FFPE samples, 5 cases were excluded due to the insufficient genomic DNA quantity. Bioinformatics results of NGS analyses of 92 patients' samples indicated 17.39% pathogenic mutations and 32.61% potentially pathogenic mutations in genes BRCA1/2. Overall, 50% pathogenic and potentially pathogenic mutations were detected in the patient's cohort. The relatively high incidence of BRCA1/2 mutations in our series may be influenced by various indicators including the selection of patients based on adjuvant therapy response as well as regional or population heterogeneity in their frequency. Based on the interdisciplinary cooperation, the use of archival biopsy material processed primarily and stored for a longer period in different laboratories without uniformly defined pre-analytical conditions allows identifying the HGSC patients who might better respond to the PARP-inhibition therapy.

Prevalence and significance of M541L single nucleotide polymorphism in the central European cohort of gastrointestinal stromal tumor patients.

BACKGROUND: Single nucleotide polymorphisms can create a genetic microenvironment in some tumors that affects the course of treatment, resistance, etc. Whether single nucleotide polymorphisms have an impact on gastrointestinal stromal tumor (GIST) development and disease progression is not yet accurately verified. KIT SNPM541L in exon 10 correlates with a worse prognosis of many cancers. The impact of KIT SNPM541L in GISTs is relatively unknown and, therefore, its analyses could have potential in patient therapy and could provide more detailed information on tumor character, clinical presentation, or tumor behavior in treatment. AIM: The aim of the study was the analysis of the biological and clinical significance of the KIT SNPM541L polymorphism in exon 10. MATERIALS AND METHODS: Paraffin sample tissues were obtained from the National GIST Register in Martin. Retrospective samples from 177 GIST patients were divided into several groups. Detection of SNPM541L was performed by Sanger sequencing. Statisitical analyses were performed to determine the prevalence of KIT SNPM541L in the Slovak GIST cohort, to search for correlation between c-KIT status and clinicopathological, molecular and biological data. RESULTS: Overall, 29 samples out of 177 showed KIT SNPM541L polymorphism. CONCLUSION: Our results do not support the association between KIT SNPM541L and increased risk of relapse in localized primary GISTs. Additionally, we found a positive correlation between KIT SNPM541L occurrence and earlier onset of relapse in PDGFRa and WT subgroup of GISTs.

Cold Atmospheric Pressure Plasma (CAP) as a New Tool for the Management of Vulva Cancer and Vulvar Premalignant Lesions in Gynaecological Oncology.

Vulvar cancer (VC) is a specific form of malignancy accounting for 5-6% of all gynaecologic malignancies. Although VC occurs most commonly in women after 60 years of age, disease incidence has risen progressively in premenopausal women in recent decades. VC demonstrates particular features requiring well-adapted therapeutic approaches to avoid potential treatment-related complications. Significant improvements in disease-free survival and overall survival rates for patients diagnosed with post-stage I disease have been achieved by implementing a combination therapy consisting of radical surgical resection, systemic chemotherapy and/or radiotherapy. Achieving local control remains challenging. However, mostly due to specific anatomical conditions, the need for comprehensive surgical reconstruction and frequent post-operative healing complications. Novel therapeutic tools better adapted to VC particularities are essential for improving individual outcomes. To this end, cold atmospheric plasma (CAP) treatment is a promising option for VC, and is particularly appropriate for the local treatment of dysplastic lesions, early intraepithelial cancer, and invasive tumours. In addition, CAP also helps reduce inflammatory complications and improve wound healing. The application of CAP may realise either directly or indirectly utilising nanoparticle technologies. CAP has demonstrated remarkable treatment benefits for several malignant conditions, and has created new medical fields, such as "plasma medicine" and "plasma oncology". This article highlights the benefits of CAP for the treatment of VC, VC pre-stages, and postsurgical wound complications. There has not yet been a published report of CAP on vulvar cancer cells, and so this review summarises the progress made in gynaecological oncology and in other cancers, and promotes an important, understudied area for future research. The paradigm shift from reactive to predictive, preventive and personalised medical approaches in overall VC management is also considered.

Genetic and epigenetic analysis of the beta-2-microglobulin gene in microsatellite instable colorectal cancer.

One of the most common mechanisms of immune evasion in MSI colorectal cancers (CRCs) is loss of HLA class I expression due to mutations in B2M gene which can become a negative predictor for checkpoint blockade therapy. The aim of this study was the determination of prevalence of B2M somatic mutations in MSI CRC patients and relationship between B2M mutations and lymphocytes infiltration and other clinicopathological features as well as detection of methylation changes in B2M promoter region which can be another mechanism of immune escape. In our study, 37 MSI-H and 5 MSI-L patients were selected for screening of B2M mutational and methylation status. The characterization of patients was based on standard histopathological diagnosis and TNM classification; BRAF, KRAS mutations, tumor-infiltrating lymphocytes and peritumoral lymphoid reaction were also determined. MSI analysis was performed using fragment analysis. B2M mutations were identified by Sanger sequencing, and methylation of CpG islands in promoter region was detected by methylation-specific PCR. Heterozygous mutations in the B2M gene were detected in five MSI-H patients (13.5%), while the mutation c.45_48delTTCT was determined in four patients and mutation c.276delC was found in two patients. One of these five patients was compound heterozygote harboring both mutations. Methylation of the promoter region of the B2M gene was observed in one patient with MSI-H colorectal cancer. Detection of genetic and epigenetic changes in B2M gene could be important in personalized therapy for CRC patients as these changes may be one of the mechanisms of secondary resistance of MSI positive tumors to immunotherapy.

Mutation analysis of POLE gene in patients with early-onset colorectal cancer revealed a rare silent variant within the endonuclease domain with potential effect on splicing.

The colorectal cancer harbor germline, somatic or epimutations in mismatch repair genes, MUTYH or POLE gene, which lead to the hypermutated and ultramutator phenotypes with increased immune response. The mutations in POLE gene were reported to occur more frequently in early-onset colorectal cancer (EOCRC), and the patients are strong candidates for checkpoint inhibitor therapy. Here, we report mutation analysis within the endonuclease domain of the POLE gene in the cohort of patients with EOCRC in order to identify recurrent or new mutations and evaluate their association with the presence of tumor-infiltrating lymphocytes (TILs) and peritumoral lymphoid reaction. We have shown a significant association between MSI tumors and TILs (p = 0.004). Using sensitive single-tube nested PCR with subsequent Sanger sequencing, we have found in one female patient diagnosed at age 48 with rectal adenocarcinoma with mucinous elements staged pT3pN2pM1 a silent variant within the exon 9 NM_006231.3 c.849 C > T, NP_00622.2 p.Leu283 = recorded in dSNP as rs1232888774 with MAF = 0.00002. In silico prediction, result showed possible involvement into splicing; therefore, this rare variant can be involved into EOCRC pathogenesis. In the time of precise medicine, it is important to develop screening strategies also for less common conditions such as EOCRC allowing to predict tailored therapy for younger patients suffering from CRC that harbor mutations in the POLE gene.

Stratification of patients with colorectal cancer without the recorded family history.

Colorectal cancer (CRC) is a multifactorial disease and one of the most malignant tumours. In addition to the sporadic form, familial occurrences, particularly hereditary non-polyposis CRC-Lynch syndrome (LS)-are often observed. LS is caused by a germline mutation in mismatch repair (MMR) genes, whose task it is to correct errors in the DNA structure that result from its replication. The aim of the present study was to stratify CRC patients using molecular diagnostics and next generation sequencing, according to the chosen criteria [positive for microsatellite instability (MSI) and negative for a BRAF mutation and MutL homolog 1 (MLH1) methylation], and subsequently to detect pathological germline mutations in MMR genes in Slovak patients. To exclude patients with MSI from further testing, the present study detected the BRAF V600E mutation and examined MLH1 methylation status. From the 300 CRC patients, 37 cases with MSI were identified. In the MSI-positive samples, 13 cases of BRAF V600E mutation were recorded. In 24 BRAF-negative patients, 11 cases of epigenetic methylation of MLH1 and 12 cases without MLH1 methylation suspected for LS were detected, and it was not possible to analyse the methylation phenotype of 1 sample. Thus, the present study reports the novel deletion of four nucleotides, 1627_1630del AAAG (Glu544Lysfs*26) in MSH6, probably associated with LS. A second case with a nonsense mutation in MSH was also detected, namely MMR_c.1030C>T (p.Q344X).

Droplet digital PCR revealed high concordance between primary tumors and lymph node metastases in multiplex screening of KRAS mutations in colorectal cancer.

The proto-oncogene KRAS belongs among the most frequently mutated genes in all types of cancer and is also very important oncogene related to colorectal tumors. The detection of mutations in this gene in primary tumor is a predictive biomarker for the anti-EGFR therapy in metastatic CRC (mCRC); however, the patients with wild-type KRAS can also show resistance to the personalized medicine. The droplet-based digital PCR technology has improved the analytical sensitivity of the mutations detection, which led us to the idea about the optimization of this approach for KRAS testing. In this study, we report the application of ddPCR technology in order to analyze the presence of KRAS mutations in primary tumor and matched metastasis in lymph nodes (LNs) from patients with mCRC and address the question, whether the improvement in the detection method can lower the discrepancies of KRAS mutations detection between the primary tumor and regional LNs. Genomic DNA with wtKRAS and commercial DNA with mtKRAS (G12D) were used to set up the ddPCR reaction. Formalin-fixed paraffin-embedded tissues from primary tumor and positive lymph node from 31 patients with mCRC were analyzed using ddPCR and Sanger sequencing. KRAS status of primary tumors was known; however, the mutation status of lymph nodes was not detected previously. From 31 samples of primary tumors, our results corresponded to results from IVD kit in 30 cases. For one patient, ddPCR detected KRAS mutation in comparison with negative result of the IVD kit. In the samples of metastatic infiltrated LNs, ddPCR detected 16 samples as a WT KRAS and 15 lymph nodes showed positivity for KRAS mutation, whereby Sanger sequencing found KRAS mutations in 8 cases only. We also found two cases where genetic conditions of KRAS gene differed between primary tumor and infiltrated lymph node, both "low-grade" adenocarcinoma. Our study approved that ddPCR method is adequate technique with high sensitivity and in the future may be used as a diagnostic tool for evaluation of KRAS mutations, especially in infiltrated LNs of patients with mCRC.

Methylation of the first exon in the erythropoietin receptor gene does not correlate with its mRNA and protein level in cancer cells.

BACKGROUND: Erythropoietin receptor (EPOR) is a functional membrane-bound cytokine receptor. Erythropoietin (EPO) represents an important hematopoietic factor for production, maturation and differentiation of erythroid progenitors. In non-hematopoietic tissue, EPO/EPOR signalization could also play cytoprotective and anti-apoptotic role. Several studies identified pro-stimulating EPO/EPOR effects in tumor cells; however, numerous studies opposed this fact due to the usage of unspecific EPOR antibodies and thus potential absence or very low levels of EPOR in tumor cells. It seems that this problem is more complex and therefore we have decided to focus on EPOR expression at several levels such as the role of methylation in the regulation of EPOR expression, identification of possible EPOR transcripts and the presence of EPOR protein in selected tumor cells. METHODS: Methylation status was analysed by bisulfite conversion reaction, PCR and sequencing. The expression of EPOR was monitored by quantitative RT-PCR and western blot analysis. RESULTS: In this study we investigated the methylation status of exon 1 of EPOR gene in selected human cancer cell lines. Our results indicated that CpGs methylation in exon 1 do not play a significant role in the regulation of EPOR transcription. However, methylation status of EPOR exon 1 was cell type dependent. We also observed the existence of two EPOR splice variants in human ovarian adenocarcinoma cell line - A2780 and confirmed the expression of EPOR protein in these cells using specific A82 anti-EPOR antibody. CONCLUSION: We outlined the methylation status of all selected cancer cell lines in exon 1 of EPOR gene and these results could benefit future investigations. Moreover, A82 antibody confirmed our previous results demonstrating the presence of functional EPOR in human ovarian adenocarcinoma A2780 cells.

Next Generation Sequencing in Molecular Diagnosis of Lynch Syndrome - a Pilot Study Using New Stratification Criteria.

The development of the new technologies such as the next-generation sequencing (NGS) makes more accessible the diagnosis of genetically heterogeneous diseases such as Lynch syndrome (LS). LS is one of the most common hereditary form of colorectal cancer. This autosomal dominant inherited disorder is caused by deleterious germline mutations in one of the mismatch repair (MMR) genes - MLH1, MSH2, MSH6 or PMS2, or the deletion in the EPCAM gene. These mutations eventually result in microsatellite instability (MSI), which can be easily tested in tumor tissue. According to the actual recommendations, all patients with CRC that are suspect to have LS, should be offered the MSI testing. When the MSI is positive, these patients should be recommended to genetic counseling. Here we report a pilot study about the application of NGS in the LS diagnosis in patients considered to have sporadic colorectal cancer. The inclusion criteria for the NGS testing were MSI positivity, BRAF V600E and MHL1 methylation negativity. We have used 5 gene amplicon based massive parallel sequencing on MiSeq platform. In one patient, we have identified a new pathogenic mutation in the exon 4 of the MSH6 gene that was previously not described in ClinVar, Human Gene Mutation Database, Ensembl and InSight databases. This mutation was confirmed by the Sanger method. We have shown that the implementation of new criteria for colorectal patients screening are important in clinical praxis and the NGS gene panel testing is suitable for routine laboratory settings.