[16-19] However, the majority of MSP primer sets used have failed to discriminate between PTEN and its frequently methylated pseudogene, leading to a high rate of false positives.[20] In the present study, we used MSP primers specifically designed to amplify the protein-encoding PTEN gene,[21] and showed that PTEN was not subject to promoter hypermethylation in colorectal carcinomas. The gene discussed is PTEN; the disease is colorectal carcinoma.