PTEN and neoplasm: Detection of the PTEN mRNA by qRT–PCR revealed that the expression of PTEN in clinical tumour samples was significantly decreased in N2–3 stages as compared with either N0–1 stages (0.1673±0.0295 versus 0.3927±0.0435, P<0.0001) or NP (0.1673±0.0295 versus 1.2100±0.1247, P<0.0001; Fig. 3e, left panel).