A 4-miRNA signature act as a novel prognostic biomarker in patients with Sarcoma.

BACKGROUND: A sarcoma is a rare form of cancer that can develop throughout the body and has a poor prognosis. Micro RNA may be used as molecular markers in sarcoma patients to predict patient outcomes. METHODS: In this study, miRNA expression data of sarcoma tissues samples were downloaded from The Cancer Genome Atlas (TCGA) database. The univariable cox regression and log likelihood were performed to screen the miRNAs related with prognosis. The Cox proportional hazard regression model was used to establish a multi-gene prognostic model based on the expression value of the miRNAs. The survival curve was created by the KM method. The interaction network and function annotation of the target genes were analyzed to investigate the mechanism of the key miRNAs. RESULTS: Hsa-miR-190b, hsa-miR-3170, hsa-miR-4762, hsa-miR-18a were identified and used to establish the prediction model. The target genes of the 4 miRNAs were involved in cancer signaling pathways as revealed by KEGG. Cox regression analysis showed that the prognostic model of miRNA was an independent influencing factor in Sarcoma patients (P<0.05). Survival analysis confirmed that the overall survival rate of sarcoma patients with low risk scores was significantly higher than those with high risk scores (P<0.01). CONCLUSIONS: The miRNA prognosis model established in this study can be used to predict the prognosis of Sarcoma patients, and these 4 miRNAs may involve in cancer signaling pathways by regulating these target genes.

[Sequence variation of D12S391 and D11S554 loci in Guangzhou han population].

To study the core sequence of the hypervariable short tandom repeats, we sequenced the alleles of D12S391 and D11S554 loci which show high mutation rate in Guangzhou Han population. The D12S391 locus has the basic sequence structure (AGAT)8-17 (AGAC)6-10 (AGAT)0-1. The smaller alleles (15-18) at D12S391 locus have variation limited to the number of the first repeat (AGAT), whereas the larger alleles (19-27) have more complex variation in the number not only of the first repeat but also of the other two repeats (AGAC) and (AGAT). Four new alleles named 22", 23", 24"' and 27 respectively were found. The D11S554 locus has more complex core sequence classified into five sequence types. Three of them have the same basic sequence structure (AAAGG) (AAAG)4 (AAAGG)2-3 (AAAG)13-19. In the larger alleles (219-249), there are four and five nucleotide repeats. Some of the larger alleles(219-249) have one base variation, bases insert or deletion. The two loci all have sequence heterogeneity. Our results indicated that the two loci D12S391 and D11S554 belong to complex repeats and this adds difficulty to their correctly typing. It is essential to construct allelic ladder in each population.

[Study on the mutation of human short tandem repeats at three loci].

OBJECTIVE: To understand the mutational patterns and mechanism of short tandem repeats(STRs). METHODS: The DNA samples of 19 parent-child pairs with mutations in three loci (FGA, D12S391, and D11S554) were genotyped by silver staining on STR. Alleles to be sequenced were excised from gels, reamplified by PCR, and purified. Sequencing was performed by use of cycle sequencing. RESULTS: There were 18 out of 19 pedigrees in which the 'new' alleles gained or lost a single repeat (8 gains, 7 losses, and 3 being indistinguishable). Only one pedigree lost two repeats. In the 19 pedigrees, there were 13 pedigrees whose 'new' alleles came from fathers, 3 from mothers, 3 from either father or mother. The ratio was 4 1 between fathers and mothers. The mutation of three STR loci occurred in the long, uninterrupted tetranucleotide repeat regions ('CTTT' in FGA, 'AGAT' in D12S391, and 'AAAG' in D11S554). CONCLUSION: Single- step mutations accounted for 95% of STR mutation events in these three loci: FGA, D12S391, and D11S554. The rest were double step mutations. There was no insertion or deletion of an incomplete repeat in any of the pedigrees. The mutation was mainly caused by fathers. The long, uninterrupted tetranucleotide repeats in these three loci might be susceptible to mutation.