Correlation of MLH1 polymorphisms, survival statistics, in silico assessment and gene downregulation with clinical outcomes among breast cancer cases

Identification of Candidate Genes in Early-Stage Invasive Ductal Carcinoma Patients with High-Risk Mortality Using Genes Commonly Involved in Breast Cancer: A Retrospective Study

INTRODUCTION

Invasive ductal carcinoma (IDC) of the breast is a heterogeneous disease characterized by multiple subtypes. IDC survival is highly impacted by tumor burden, molecular subtypes, and gene profiles. Gene mutation is a type of genomic instability regarded as having a considerable effect on IDC prognosis. Using integrated survival analysis, this study identified candidate genes and a high-risk group of patients with early-stage IDC to provide further understanding of the genetic characteristics associated with poor survival.

METHODS

The gene mutation profiles, baseline demographics, clinicopathologic variables, and treatment characteristics of the early-stage IDC subpopulation were downloaded from an open access data platform. These data were analyzed for a total of 444 patients. In total, 40 genes commonly involved in IDC were listed, and the genes exhibiting significant differences (as estimated using the log-rank test) were selected as the candidate genes.

RESULTS

The patients were divided into control, low-risk, and high-risk groups according to their gene mutation profiles. The 5-year overall survival rates of low-risk, control, and high-risk patients were 97.4%, 96.1%, and 73.0%, respectively. The high-risk group had a significantly higher risk of poor overall -survival (adjusted hazard ratio = 6.57, 95% confidence interval = 1.51-28.7, p = 0.012) than that of the control group, and the low-risk group did not have a significant survival difference compared with control group.

CONCLUSIONS

This study proposed an integrative approach for the identification of candidate genes for risk assessment of overall survival in these patients through typical survival analysis methods. The 14 candidate genes selected are particularly involved in cell-cycle processes, deoxyribonucleic acid repair, and drug resistance; their mutations were found to be generally associated with disease progression or therapeutic resistance, which is commonly associated with poor overall survival outcomes in IDC.

A novel long non-coding RNA TTN-AS1/microRNA-589-5p/FOXP1 positive feedback loop increases the proliferation, migration and invasion of pancreatic cancer cell lines

Numerous reports have found that long non-coding (lnc) RNAs were associated with pancreatic cancer (PC) initiation and development. The lncRNA titin antisense RNA 1 (TTN-AS1) was identified as a tumor promoter in certain types of cancer; however, its role and mechanism in PC remain unclear. The aim of the present study was to investigate the role of TTN-AS1 in PC and elucidate the underlying mechanism. Reverse transcription-quantitative PCR analysis was performed to examine the mRNA expression level of TTN-AS1, microRNA(miR)-589-5p and forkhead box protein 1 (FOXP1). Knockdown experiments were performed to examine the effect of TTN-AS1 on PC cell proliferation, migration and invasion. Luciferase reporter assays validated the binding of miR-589-5p to TTN-AS1 and FOXP1. Chromatin immunoprecipitation and luciferase reporter assays confirmed the binding ability of FOXP1 to the TTN-AS1 promoter. As a result, TTN-AS1 and FOXP1 were found to be upregulated in PC cell lines and tissues, while miR-589-5p was expressed at low levels. Knockdown experiments indicated the suppressive effect of TTN-AS1 knockdown on cell proliferation, migration and invasion in PC cell lines. Further mechanistic research uncovered that TTN-AS1 functioned as a molecular sponge for miR-589-5p and its mRNA expression level in PC tissues was inversely associated with that of miR-589-5p. Furthermore, miR-589-5p was confirmed to target FOXP1. Of note, it was discovered that FOXP1 transcriptionally activated TTN-AS1 mRNA expression level. Taken together, the findings of the present study demonstrated that the new TTN-AS1/miR-589-5p/FOXP1 feedback loop may play an important role in PC.

Correlation of MSH2 exonic deletions and protein downregulation with breast cancer biomarkers and outcome in Pakistani women/patients

Mismatch repair (MMR) pathway is one of the underlying mechanisms of predisposition to breast cancer (BC). The present study explored the association of MSH2 exonic deletions, respective survival analysis, protein structure prediction, transcription profiling, and expression analysis with BC risk. Genotyping analysis of 493 BC cases and 387 controls confirmed the association of two MSH2 exonic deletions, i.e., exon 3 (OR:6.4, CI = 3.4-12.1) and 9 (OR:7.8, CI = 4.1-14.8) with BC risk. In order to confirm the phenotypic-genotypic relationship, we have performed MSH2 transcriptomic (p < 0.05) and protein expression analysis (OR:30, CI = 4-230) which further confirmed its downregulation/loss in BC biopsy samples highlighting potential role in the onset of breast carcinogenesis. Additionally, we have presented that MSH2 mutations can alter the expression profile of other BC associated biomarkers like ER, PR, CK-7, GATA-3, and E-cadherin. Subsequently, the effect of exonic deletions on secondary structure of protein has shown missing of beta and alpha helices in their protein products via in-silico analysis. However, loss of exon 3 results in the altered core protein structure leading to dysfunction protein, possible cause of BC development. No association of MSH2 exonic deletions with survival statistics was observed conceivably due to the shorter follow-up time. Thus, our results at genetic, transcriptomic, and proteomic levels confirmed the downregulated MSH2, emphasizing its potential contribution in MMR mechanisms for breast tumorigenesis. In conclusion, MSH2 deficiency may cause breast cancer development and progression.