No abstract

The histone methyltransferase enhancer of zeste 2 (EZH2) is known to be a polycomb protein homologous to Drosophila enhancer of zeste and catalyzes the addition of methyl groups to histone H3 at lysine 27 (H3K27). We previously reported that EZH2 was overexpressed in various types of cancer and plays a crucial role in the cell cycle regulation of cancer cells. In the present study, we demonstrated that EZH2 has the function to monomethylate lysine 120 on histone H2B (H2BK120). EZH2-dependent H2BK120 methylation in cancer cells was confirmed with an H2BK120 methylation-specific antibody. Overexpression of EZH2 significantly attenuated the ubiquitination of H2BK120, a key posttranslational modification of histones for transcriptional regulation. Concordantly, knockdown of EZH2 increased the ubiquitination level of H2BK120, suggesting that the methylation of H2BK120 by EZH2 may competitively inhibit the ubiquitination of H2BK120. Subsequent chromatin immunoprecipitation-Seq and microarray analyses identified downstream candidate genes regulated by EZH2 through the methylation of H2BK120. This is the first report to describe a novel substrate of EZH2, H2BK120, unveiling a new aspect of EZH2 functions in human carcinogenesis.

Folate metabolism is fundamental and essential for DNA structure synthesis and repair. Change in genes that participate in folate metabolism can be linked with different types of malignant tumor, Therefore, this study was conducted to find out the association between methylenetetrahydrofolatereductaseMTHFR gene polymorphisms and risk of breast cancer in a sample of Iraqi patients. One Single Nucleotide Polymorphism (SNP) including MTHFR C677T was calculated using a tetra primer ARMS PCR experiment assay. The results explained that (MTHFR C677T) consists of three genotype (CC, CT, TT), The CC genotype was the most frequent in patients and control group (40.00%) and(60.00%) ,respectively, while the lowest frequency was for TT genotype(26.25%) in patients group .This study also revealed that the higher frequency 56.88 % for allele C and 43.12 % for T allele in patients group. On the other hand the Odd Ratio (O.R.) for CC, CT , TT genotypes were 1.073, 0.862 and 1.148 respectively, and the genotypes TT show a highest O.R.

Background:Preterm neonates comprise the most heavily transfused group of patients, and about 85% of extremely low birth weight newborns receive a transfusion by the end of their hospital stay. The aim of this study was to assess the possible metabolic effects of RBC transfusion on preterm infants, especially during the first 2 weeks of life, and its relation to blood volume.Materials and Methods:This study was conducted on 40 preterm neonates with gestational age of less than or equal to 34 weeks. They received RBCs transfusion during first 2 weeks of life. Venous blood samples of infants were collected 2 to 4 hours before and 1 hour after the end of transfusion to evaluate hemoglobin (Hb) level, hematocrit, acid-base, electrolytes, and glucose status. Then, infants were classified into two main groups: those who received RBCs volume less than or 20 ml/kg and those who received RBCs volume more than 20 ml/kg.Results:Infants received a mean volume of 20.38 ± 3.2 ml/kg RBCs (range, 10.9 - 26.6 ml/kg) at a median age of 9.8 ± 3.6 days. After transfusion, a significant increase of mean Hb (P<0.001), mean Hct (P<0.001), pH (P<0.001), pO2 (P<0.05), and a significant decrease of the pCO2 (41.46 ± 8.8torr vs 35.4 ± 9.34 torr; P<0.001) were observed. In addition, there was a significant increase of serum K+ (P<0.001), and a significant decrease of Ca+2 (P<0.001). A positive correlation was found between the K+ intake and the changes of kalemia (r = 0.99; P = 0.00). Furthermore, we observed an inverse correlation between the patients’ calcium intake and the changes of calcemia (r = -0.35; P = 0.02). On comparing the changes in clinical and biochemical variables between two groups after transfusion, we observed a significant increase in mean Hb and Hct associated with a significant decrease in mean serum Ca+2 (P<0.001) in the group receiving the larger blood volume.Conclusion:RBC transfusion was effective in improving anemia, oxygenation, increasing pH, and decreasing CO2 and Ca+2. However, from a more clinically relevant point of view, we demonstrated the development of hyperkalemia, especially in infants with a previously borderline hyperkalemia.

No abstract