ABSTRACT Aberrant methylation is one of the driving forces of cancer genome development. Although the rate of methylation appears massively variable across the genome, it is mainly observed in histone modification, chromatin organization, DNA accessibility, or promoter sequence. Methylation of promoter sequence occurs mostly to cytosine nucleotides, which can affect transcription factors' binding affinities. In this study, we demonstrated that cytosine repeats (C types density), consisting of CC, CCC, CCCC, CCCCC, CCCCCC, CCCCCCC motifs and CpG islands density in 25 proto-oncogenes, tumor suppressor genes and control genes may play a role in the pathogenesis of acute myeloid leukemia. The promoter sequences were divided into a 100 nucleotide window from −500 to +100 nucleotides and 20 nucleotide window from −100 to +100. Each window is analyzed to find the higher C type and CpG islands density, which may cause the increased methylation in the promoter sequence. Our novel findings show that promoter sequence cytosine repeats and CpG density increase closer to transcription sites, especially just before and after the transcription start site (TSS). The results demonstrate that cytosine density increases while proto-oncogenes and TSG promoter sequences are closer to TSS 50.8% and 41.0% respectively, if (−500 to −200) and (−100 to +100) windows of the nucleotide sequences are compared. This proves that around TSS location has special nucleotide motifs and could be an important implication for our understanding of potential methylating locations in promoters.

Background: Heteromorphic variants including Yq12 material, being inserted or added to autosomal chromosomes have been reported for chromosomes 1, 7, 11, 13, 14, 15, 21 and 22. Here we describe a novel insertion of Yq12 heterochromatin into a chromosome 17; to the best of our knowledge no similar cases have been reported previously. Methods: GTG-, C-banding, fluorescence in situ hybridization (FISH), and homemade human heterochromatin specific multicolor FISH probes set (HCM-mix) were used to define the abnormality. A whole chromosome painting (wcp) probe for #17 together with a probe for Yq12 heterochromatin was hybridized to the patient sample. Additionally, Y microdeletion PCR was done to detect possible AZF subregional deletions. Results: The male patient had normal sperm analysis and no AZF deletions on Y chromosome. GTG and Cbanding showed an additional band on chromosome 17q21. FISH studies revealed that the insertion was derived from Yq12 heterochromatin. Conclusions: The heterochromatin insertion on 17q21 originating from Yq12 chromosome did not affect the spermatogenesis of aberration carrier and is probably not the cause of infertility in these partners. However, a new heteromorphic variant was identified in this case.

Gaucher disease is a hereditary genetic abnormality which defects the pathway of sphingolipid catabolism. The mutation of GBA gene which encodes lysosomal β-glucosidase enzyme is the main characteristics of the disease also is observed in different cancer types. To find the relation between the disease and colon adenocarcinoma, the responsible gene expression of Gaucher disease was analyzed. The gene expression of colon adenocarcinoma was was compared between death and alive patients and analyzed statistically to profile the differences between Gaucher disease genes expression changes. GBA, GBA2, GBA3, SCARB2 and PSAP have the maximum genetic alteration which is observed in colon adenocarcinoma.

Mixed-lineage leukemia (MLL) is a subtype of acute myeloid leukemia with more aggressive prognosis than other subtypes. Translocations of MLL gene with other partner genes, forming the MLL-fusion proteins (MLL-FPs), are the main characteristics of MLL leukemia. Many studies have demonstrated that MLL-FPs such as: MLL-AF4, MLL-AF6, MLL-AF9, MLL-AF10, MLL-ENL, MLL-ELL, MLL-EPS15, as well as partial tandem duplication are the most common abnormalities that play significant role in MLL-rearranged leukemia. Gene expression profiles from 197 patients and 180 clinical data were downloaded from TCGA database. R statistical program has classified clinical and genomic data simultaneously according to cytogenetic abnormalities. As a result of this analysis, the most frequent 47 MLLFPs genes expression have been detected and compared with other cytogenetic abnormalities such as t(4;11), t(9;11), t(8;21), t(15;17), complex, inversion 16, trisomy 8 and cytogenetically normal AML. 35 out of 46 MLL-FPs genes presented with abnormal gene expression profile. This study showed that MLL-FPs are not just active and related with MLL, but also with other subtypes of AML.

Invasive breast cancer is a heterogeneous disease. The analysis of one or a group of specific gene expression profiles may not be enough to understand molecular activities in cancer cells. Therefore, a method which gives us the opportunity to compare similar up and down regulated gene expression profiles, is needed. The main purpose of our work is to sort the extreme high and low expressed genes and extract, compare and cluster them. Expression profiles of 598 samples of invasive breast cancer and 48 samples of normal tissue have been analysed to create a new algorithm called Extreme Gene Expression Family (EGEF). The EGEF algorithm sorted, grouped and compared the highest and the lowest expressed genes (n = 100). According to the hierarchical clustering result, dense and light memberships of gene families are detected. The resulting analysis allows us to predict which genes would show similar expression signatures in invasive breast cancer and to us to recognize specific biological activities and processes. EGEF algorithm can be used to detect expression signatures in other cancers and biological processes.

Invasive breast cancer is a heterogeneous disease. The analysis of one or a group of specific gene expression profiles may not be enough to understand molecular activities in cancer cells. Therefore, a method which gives us the opportunity to compare similar up and down regulated gene expression profiles, is needed. The main purpose of our work is to sort the extreme high and low expressed genes and extract, compare and cluster them. Expression profiles of 598 samples of invasive breast cancer and 48 samples of normal tissue have been analysed to create a new algorithm called Extreme Gene Expression Family (EGEF). The EGEF algorithm sorted, grouped and compared the highest and the lowest expressed genes (n = 100). According to the hierarchical clustering result, dense and light memberships of gene families are detected. The resulting analysis allows us to predict which genes would show similar expression signatures in invasive breast cancer and to us to recognize specific biological activities and processes. EGEF algorithm can be used to detect expression signatures in other cancers and biological processes.

Microdeletion syndromes are caused by chromosomal deletions of less than 5 megabases which can be detected by fluorescence in situ hybridization (FISH). We evaluated the most commonly detected microdeletions for the period from June 01, 2008 to June 01, 2015 in the Federation of Bosnia and Herzegovina, including DiGeorge, Prader-Willi/Angelman, Wolf-Hirschhorn, and Williams syndromes. We report 4 patients with DiGeorge syndromes, 4 patients with Prader-Willi/Angelman, 4 patients with Wolf-Hirschhorn syndrome, and 3 patients with Williams syndrome in the analyzed 7 year period. Based on the positive FISH results for each syndrome, the incidence was calculated for the Federation of Bosnia and Herzegovina. These are the first reported frequencies of the microdeletion syndromes in the Federation of Bosnia and Herzegovina.

BACKGROUND Periapical inflammatory lesions have been investigated previously, but understanding of pathogenesis of these lesions (granulomas and radicular cysts) at the molecular level is still questionable. Matrix metalloproteinases (MMPs) are enzymes involved in the development of periapical pathology, specifically inflammation and tissue destruction. To elucidate pathogenesis of periapical granulomas and radicular cysts, we undertook a detailed analysis of gene expression of MMP-1, MMP-2 and their tissue inhibitors, TIMP-1 and TIMP-2. METHODS A total of 149 samples were analyzed using real-time PCR (59 radicular cysts, 50 periapical granulomas and 40 healthy gingiva samples as controls) for expression of MMP-1, MMP-2, TIMP-1 and TIMP-2 genes. The determination of best reference gene for expression analysis of periapical lesions was done using a panel of 12 genes. RESULTS We have shown that β-actin and GAPDH are not the most stable reference controls for gene expression analysis of inflammatory periapical tissues and healthy gingiva. The most suitable reference gene was determined to be SDHA (a succinate dehydrogenase complex, subunit A, flavoprotein [Fp]). We found that granulomas (n = 50) and radicular cysts (n = 59) exhibited significantly higher expression of all four examined genes, MMP-1, MMP-2, TIMP-1, and TIMP-2, when compared to healthy gingiva (n = 40; P < 0.05). CONCLUSION This study has confirmed that the expression of MMP-1, MMP-2, TIMP-1, and TIMP-2 genes is important for the pathogenesis of periapical inflammatory lesions. Since the abovementioned markers were not differentially expressed in periapical granulomas and radicular cysts, the challenge of finding the genetic differences between the two lesions still remains.

Cancer patients in developing and low‐income countries have limited access to target therapies. For example, tyrosine kinase inhibitor (TKI) therapy for chronic myeloid leukaemia patients (CML) is often delayed. In Bosnia, 16% of patients received immediate TKI treatment (<3 months of diagnosis), while 66% of patients received therapy after a median 14‐month wait period. To assess the effect of delayed treatment on outcome, three patient groups were studied according to the time they received TKI treatment (0–5 months, 6–12 months and >13 months delay). The primary endpoints were complete cytogenetic (CCyR) and major molecular response (MMR) at 12 months. At 12 months of therapy, CCyR and MMR rates on imatinib decreased significantly: CCyR was achieved in 67% of patients in the immediate imatinib treatment group, 18% of patients in 6–12 months group and 15% of patients in >13 months wait group. MMR rates at 12 months occurred in 10% of patients with immediate treatment, 6% of those in 6–12 months group and 0% of patients in >13 months wait group. However, CCyR and MMR rates in patients on nilotinib were not associated with duration of treatment delay. Our data suggests that the deleterious effect of a prolonged TKI therapy delay may be ameliorated by the more active TKI nilotinib.

The guanine rich locations are present in human genome. Previous studies have shown that the presence of G rich sequences and motifs may be significant for gene activity and function. We decided to focus our interest to identify G rich motifs in promoters of oncogenes and tumor suppressor genes. We used a set of 100 most common oncogenes and tumor suppressor genes (TSG) for this analysis. We collected 600nt long promoters with -500 and +100 TSS (transcription start site) from the oncogenes and TSG set. Using a computer program, we calculated the G densities using numbers and locations of G forms with 100nt moving widow. We included G numbers from 2 to 7 guanines. Analysis shows that G density increases from -500 to +100 and more from TSS. G density is found to be maximum within -/+100 of TSS. The results of G densities were compared with the expression data of the selected oncogenes and tumor suppressor genes in patients with colon cancer (n=174).

Mixed lineage leukemias (MLL) express unique clinical and biological characteristics. MLL interacts with over 50 different genes resulting in expression of chimeric proteins whereby the MLL amino-terminal portion is fused to the carboxy-terminal portion of the partner. Chromosomal translocations t(9 ; 11), t(11 ; 19) and t(4 ; 11) leading to MLL-AF9, MLL-ENL and MLL-AF4 fusions are the most frequent. Leukemias with MLL rearrangements are mostly driven through dysregulation of a transforming gene expression program, making it a unique epigenetic model of leukemia. Using the whole genome profiling of acute myeloid leukemias (AMLs), we analysed the differential gene expression, methylation pattern, and mutational spectra between MLL and other AML types (n=197). We found that 120 genes were differentially expressed, with 36 genes characterized by more than twofold expression difference. In this study, we will present differently expressed genes with and their potential role in leukemogenesis. Since rearrangements of the MLL gene lead to aberrant methylation, we investigated differential methylation patterns among MLL and other AML types and identified affected methylation hotspots.