Kaplan-Meier survival analysis

The Kaplan-Meier Plotter online tool specific for NSCLC (www.kmplot.com) was used to analyse any potential correlation between overall survival and specific gene expression. This tool was generated using compiled data from multiple cancer patient transcriptomic studies and R statistical software [³⁴]. Gene expression was designated to be low or high in patients based on their relation to the median value. The KM Plotter tool then generated survival curves, and logrank P values and hazard ratios (HR) with 95% confidence intervals were calculated and plotted in R.

Survival rates and expression data for miR-146a-5p were obtained from The Cancer Genome Atlas (TCGA) and analysed using R programming language and the TCGA-Assembler 2 package [⁴⁸]. Raw miR-Seq datasets (mir_GA.hg19.mirbase20, mir_HiSeq.hg19.mirbase20) were selected for NSCLC. The miR-Seq datasets were combined and miR-146a expression was extracted. Clinical data were also extracted using TCGA-Assembler 2. Clinical data were matched with miR-146a expression data and analysed using the R packages ‘survminer’ and ‘survival’. Analysed data were graphed using ‘ggplot2’. Significance and confidence intervals were determined using the ‘survminer’ interval pvalue and conf.int functions. These functions compute significance and confidence intervals using the log-rank test and 95% upper/lower bounds, respectively.