GAPDH and cancer: Cancers exhibiting MSLN-positive immunostaining had significantly higher MSLN mRNA expression (median MSLN/GAPDH ratio, 0.031; range, 0.025–0.037) than the MSLN-negative ones (median MSLN/GAPDH ratio, 0.0053; range, 0.0022–0.0085; P < 0.0001; Figure 2).