Mutational screening of germline RB1 gene in Vietnamese patients with retinoblastoma reveals three novel mutations.

Purpose: Retinoblastoma (Rb) is a rare and unique eye cancer that usually develops in the retinas of children less than 5 years old due to mutations in the RB1 gene. About 40% of affected individuals have the heritable form making genetics testing of the RB1 gene important for disease management. This study aims to identify germline mutations in RB1 in a cohort of patients with Rb from northern Vietnam. Methods: Genomic DNA was extracted from peripheral blood of 34 patients with Rb (nine unilateral and 25 bilateral cases) and their available parents. Twenty-seven exons, flanking sequences, and the promoter region of RB1 gene were screened for mutations with direct PCR sequencing. Multiplex ligation-dependent probe amplification (MLPA) was applied for patients with negative sequencing results. In the mutation-positive patients, their available parental DNA was analyzed to determine the parental origin of the mutation. Results: Germline mutations in RB1 were identified in 25 (73.53%) of 34 patients (four unilateral and 21 bilateral cases). Of these mutations, 19 were detected, including seven nonsense, six frameshift, four splice-site (one was identified in two siblings), and one missense, with Sanger sequencing. Three novel frameshift mutations were discovered in one unilateral and two bilateral patients. MLPA detected mutations in the RB1 gene in six bilateral cases, of whom five had a whole gene deletion (three familial cases) and one had a partial gene deletion (from exon 4 to exon 27) in one allele of the RB1 gene. Parental testing showed five mutations originated from the fathers and one was inherited from a mother who was mosaic for the mutation. Conclusions: This study provides a data set of germline mutations in the RB1 gene in Vietnamese patients with retinoblastoma. Screening of mutations in the RB1 gene can help to identify heritable Rb and contribute to clinical management and genetic counseling for affected families.

The Efficacy of Transplanting Human Umbilical Cord Mesenchymal Stem Cell Sheets in the Treatment of Myocardial Infarction in Mice.

The transplantation of mesenchymal stem cell (MSC) sheets derived from human umbilical cords (hUCs) was investigated in this study as a potential application in treating myocardial infarction (MI). Two groups of hUC-MSC sheets were formed by populating LunaGelTM, which are 3D scaffolds of photo-crosslinkable gelatin-based hydrogel with two different cell densities. An MI model was created by ligating the left anterior descending coronary artery of healthy BALB/c mice. After two weeks, the cell sheets were applied directly to the MI area and the efficacy of the treatment was evaluated over the next two weeks by monitoring the mice's weight, evaluating the left ventricle ejection fraction, and assessing the histology of the heart tissue at the end of the experiment. Higher cell density showed significantly greater efficiency in MI mice treatment in terms of weight gain and the recovery of ejection fraction. The heart tissue of the groups receiving cell sheets showed human-CD44-positive staining and reduced fibrosis and apoptosis. In conclusion, the hUC-MSC sheets ameliorated heart MI injury in mice and the efficacy of the cell sheets improved as the number of cells increased.