Correlation of miRNA expression with clinical features. Measurements of miRNA expression were determined by qPCR and normalised to an average of RNU43 and RNU48 expression. qPCR for each sample was performed in triplicate. (a) A significant correlation was found between miR-210 expression and survival (years) (r = -0.481, P = 0.006). (b) No significant correlation was found between miR-155 expression and survival (years). Significant correlations were found between (c) miR-155 and (d) miR-21 expression and tumour size (mm) (r = 0.408, P = 0.028 and r = 0.434, P = 0.019, respectively).