Investigation of the methylation changes in the promoter region of RB1 gene in retinoblastoma: Unraveling the epigenetic puzzle in retinoblastoma.

Retinoblastoma is an infrequent neoplasm that arises during childhood from retinal nerve cells and is attributed to the biallelic inactivation of the RB1 gene. In conjunction with anatomical anomalies, it is widely acknowledged that epigenetic modifications play a significant role in the pathogenesis of cancer. The association between methylation of the RB1 gene promoter and tumor formation has been established; however, there is currently no scholarly evidence to substantiate the claim that it is responsible for the inheritance of retinoblastoma. The initial hypothesis posited for this work was that familial retinoblastoma disease would be similarly observed in cases with RB1 promotor gene methylation, akin to RB1 mutations. The RB1 gene promoter region was subjected to methylation screening using real-time PCR in individuals diagnosed with familial retinoblastoma but lacking RB1 mutations. The study involved a comparison of the germline methylation status of the RB1 gene in the peripheral blood samples of 50 retinoblastoma patients and 52 healthy individuals. The healthy individuals were carefully selected to match the retinoblastoma patients in terms of age, sex, and ethnicity. The data obtained from both groups were subjected to statistical analysis. The study revealed that the methylation level in a cohort of 50 individuals diagnosed with retinoblastoma and 52 healthy control participants was determined to be 36.1% and 33.9%, respectively. As a result, there was no statistically significant disparity observed in RB1 promoter methylation between the patient and control groups (p = 0.126). The methylation of the promoter region of the RB1 gene in familial retinoblastoma does not exert any influence on the hereditary transmission of the disease.

Genome-wide methylation profiles in monozygotic twins with discordance for ovarian carcinoma.

Ovarian cancer is a disease that is generally diagnosed at an advanced stage, and has poor survival. Monozygotic (MZ) twins are considered to be good research models for investigating the epigenetic changes associated with diseases. In the present study, the involvement of epigenetic mechanisms in ovarian cancer etiology were evaluated using the MZ twin model. Whole-genome methylation patterns were investigated in a BRCA1 gene mutation-carrying family comprising MZ twins, only one of whom had ovarian cancer, and other healthy siblings. Whole-genome methylation patterns were assessed in peripheral blood DNA using Infinium MethylationEPIC BeadChips on an Illumina iScan device. The hypermethylated and hypomethylated genes were detected between cases and controls in four different comparison groups in order to evaluate the differences in methylation levels according to cancer diagnosis and BRCA mutation status. The obtained results showed that the differential methylations in 12 different genes, namely PR/SET domain 6, cytochrome B5 reductase 4, ZNF714, OR52M1, SEMA4D, CHD1L, CAPZB, clustered mitochondria homolog, RB-binding protein 7, chromatin repair factor, ankyrin repeat domain 23, RIB43A domain with coiled-coils 1 and C6orf227, were associated with ovarian cancer. Biological functional analysis of the genes detected in the study using the PANTHER classification system revealed that they have roles in biological processes including 'biologic adhesion', 'regulation', 'cellular components organization', 'biogenesis', 'immune system functioning', 'metabolic functioning' and 'localization'. Overall, the present study suggested that epigenetic differences, such as methylation status, could be used as a non-invasive biological markers for the early diagnosis and follow-up of ovarian cancer.

New Approach for Risk Estimation Algorithms of BRCA1/2 Negativeness Detection with Modelling Supervised Machine Learning Techniques.

BRCA1/2 gene testing is a difficult, expensive, and time-consuming test which requires excessive work load. The identification of the BRCA1/2 gene mutations is significantly important in the selection of treatment and the risk of secondary cancer. We aimed to develop an algorithm considering all the clinical, demographic, and genetic features of patients for identifying the BRCA1/2 negativity in the present study. An experimental dataset was created with the collection of the all clinical, demographic, and genetic features of breast cancer patients for 20 years. This dataset consisted of 125 features of 2070 high-risk breast cancer patients. All data were numeralized and normalized for detection of the BRCA1/2 negativity in the machine learning algorithm. The performance of the algorithm was identified by studying the machine learning model with the test data. k nearest neighbours (KNN) and decision tree (DT) accuracy rates of 9 features involving Dataset 2 were found to be the most effective. The removal of the unnecessary data in the dataset by reducing the number of features was shown to increase the accuracy rate of algorithm compared with the DT. BRCA1/2 negativity was identified without performing the BRCA1/2 gene test with 92.88% accuracy within minutes in high-risk breast cancer patients with this algorithm, and the test associated result waiting stress, time, and money loss were prevented. That algorithm is suggested be useful in fast performing of the treatment plans of patients and accurately in addition to speeding up the clinical practice.

Investigation of new candidate genes in retinoblastoma using the TruSight One "clinical exome" gene panel.

BACKGROUND: Retinoblastoma (Rb) is the most prevalent intraocular pediatric malignancy of the retina. Significant genetic factors are known to have a role in the development of Rb. METHODS: Here, we report the mutation status of 4813 clinically significant genes in six patients with noncarrier of RB1 gene mutation and having normal RB1 promoter methylation from three families having higher risk for developing Rb in the study. RESULTS: A total of 27 variants were detected in the study. Heterozygous missense variants c.1162G > A (p.Gly388Arg) in the FGFR4 gene; c.559C > T (p.Pro187Ser) in the NQO1 gene were identified. The family based evaluation of the variants showed that the variant, c.714T > G (p.Tyr238Ter), in the CLEC7A gene in first family; the variant, c.55C > T (p.Arg19Ter), in the APOC3 gene and the variant, c.1171C > T (p.Gln391Ter), in the MUTYH gene in second family; and the variant, c.211G > A (p.Gly71Arg), in the UGT1A1 gene in the third family, were found statistically significant (p < 0.05). CONCLUSION: This study might be an important report on emphazing the mutational status of other genes in patients without RB1 gene mutations and having high risk for developing Rb. The study also indicates the interaction between the retinoic acid pathway and Rb oncogenesis for the first time.

The expression level of fibulin-2 in the circulating RNA (ctRNA) of epithelial tumor cells of peripheral blood and tumor tissue of patients with metastatic lung cancer.

The Fibulins are a recently discovered family of extracellular matrix proteins. In this study, expression levels of the fibulin-2 (FBLN2) gene and its role in the formation of different metastatic foci were investigated in lung cancer patients. We analyzed 106 lung cancer patients and eight paraffin-embedded tissues, and 27 ethnical-, age- and sex-matched healthy controls for expression levels of the FBLN2 gene. cDNAs obtained from the enriched epithelial cells of peripheral blood lymphocytes and tumor tissues of patients were amplified with specific primers for the target FBLN2 gene and HPRT1 housekeeping gene using quantitative real-time polymerase chain reaction. FBLN2 gene expression levels of the enriched epithelial cells of peripheral blood lymphocytes were found to be decreased approximately twofold in all subsets of patients compared to healthy controls. Our results indicate a significant difference between patient subgroups and controls [F(4.124) = 14.846, p0.05] among patient subgroups: bone metastases versus non-metastatic groups (p = 0.997), bone versus brain metastases (p = 0994), bone metastases versus two primary tumors (p = 0.999), brain metastases versus two primary tumors (p = 0.999), brain metastases versus non-metastatic (p = 0.755), non-metastatic versus two primary tumors (p = 0.996), non-metastatic versus all other metastatic patients (p = 0.731). Moreover, we found a 50-fold upregulation of FBLN2 gene expression in paraffin-embedded tissues compared with the enriched epithelial cells of peripheral blood lymphocytes of patients. In the study, the enriched epithelial cells of peripheral blood lymphocytes of decreased FBLN2 expression was found to be correlated with metastasis. The fibulin-2 molecules might induce the metastatic potential through interaction with the other molecules in the microenvironment, nevertheless, it is needed further research whether the importance of FBLN2 on lung cancer oncogenesis and as a biomarker for metastatic lung cancer.

The expression levels of miRNA-15a and miRNA-16-1 in circulating tumor cells of patients with diffuse large B-cell lymphoma.

MicroRNAs (miRNAs) have major roles in nearly all cellular process including gene expression, and may behave as oncogene or tumor suppressor gene by binding to complementary sequences in the target mRNA. The circulating microRNA-15a (miRNA-15a) and microRNA-16-1 (miRNA-16-1) of 15 healthy adults and of 40 untreated patients diagnosed with diffuse large B-cell lymphoma (DLBC) were recruited to investigate the expression levels. The expression levels of miRNA-15a, and miRNA-16-1 genes of the untreated DLBCL patients, and healthy individuals with matched age, sex and ethnicity were examined. MicroRNA expression profiles obtained from peripheral blood were investigated. The samples were collected from 40 patients diagnosed with DLBC patients, and from 15 healthy controls. Two miRNAs were selected, and expression profile was examined using a quantitative real-time polymerase chain reaction (qPCR) based on the previous studies. Statistically significant expression level differences (p < 0.05) were detected for miRNA-16-1 in DLBCL patients and healthy control groups. miRNA-16-1 gene expression level was found approximately ninefold higher in the patient group compared to the controls; however, no statistical difference was detected in the expression profile of miRNA-15a between the both groups. On the other hand, the decreased gene expression in miRNA16-1 was observed in 88.3% of DLBCL patients. These results suggested that there was no statistically significant decrease in the miRNA-15a gene expression in DLBCL patients (p > 0.05). On the contrary to the literature, miRNA-16-1 expression level was suppressed in DLBCL group in our study, however no whole gene silencing was performed. MicroRNA-16-1 might be suggested to behave as a tumor suppressor in DLBCL in our study.

Frequency of Rearrangements Versus Small Indels Mutations in BRCA1 and BRCA2 Genes in Turkish Patients with High Risk Breast and Ovarian Cancer.

OBJECTIVE: The current rearrangement ratio of BRCA1 and BRCA2 genes is not known in the Turkish population. Rearrangements are not routinely investigated in many Turkish laboratories. This creates problems and contradictions between clinics. Therefore, the aim of this study was to evaluate the distribution and frequency of rearrangements in BRCA1 and BRCA2 genes in high-risk families and to clarify the limits of BRCA1 and BRCA2 testing in Turkey. MATERIALS AND METHODS: The study included 1809 patients at high risk of breast cancer or ovarian cancer. All patients were investigated for both small indels and rearrangements of BRCA genes using DNA sequencing and multiplex ligation-dependent probe amplification (MLPA) analysis. RESULTS: The overall frequency of rearrangements was 2% (25/1262). The frequency of rearrangements was 1.7% (18/1086) and 4% (9/206) in patients with breast cancer and ovarian cancer, respectively. The frequency of rearrangements was 3.7% (8/215) in patients with triple-negative breast cancer. The rearrangement rate was 7.7% (2/26) in patients with both breast and ovarian cancer. CONCLUSIONS: Rearrangements were found with high rates and were strongly associated with bilateral and triple-negative status of patients with breast cancer, which are signs of high risk for breast and ovarian cancer. Analysis of rearrangements should definitely be included in routine clinical practice in Turkey for high-risk families and also for improved cancer risk prediction for families.