Figure 3.

Effects of different normalization methods on the measurement of miR-198 expression levels. (A) No significant differences in the miR-198 expression levels in pleural effusion samples were detected when the data were normalized to serum volume. When the data were normalized to (B) U6 small nuclear RNA expression levels, (C) miR-192 expression levels and (D) a combination of U6 snRNA and miR-192 expression levels, significant differences between benign pleural effusion (BPE) and lung adenocarcinoma-associated malignant pleural effusion (LA-MPE) samples were observed (P<0.001). The boxes signify the upper and lower quartiles, the median is indicated by a horizontal line, and the whiskers depict the 10th and 90th percentiles. The Mann-Whiney U test P-values are indicated in the upper right corner of each plot.