Fig. 8
From: An unusual case of Cowden syndrome associated with ganglioneuromatous polyposis
Molecular genetic analyses of PTEN on DNA from blood and tumor tissue from a ganglioneuroma and the colon carcinoma. Next-generation sequencing revealed a stop mutation in PTEN, NM_000314(PTEN):c.138C > A;p.Tyr56* in the patient’s blood in a heterozygous state indicated by the allele frequency of about 47.5 % (left). This mutation has not been seen in the first Sanger-Sequencing performed in 2010 (upper left), but was confirmed by a second Sanger-Sequencing in 2014 (lower left, indicated by arrow). The ganglioneuroma (middle) and the colon carcinoma (right) showed the mutation NM_000314:c.138C > A only as a small peak in the first Sanger-Sequencing, but in a heterozygous state in the second Sanger-Sequencing, thus indicating allele drop-out in the first Sequencing. The colon carcinoma additionally showed a second somatic mutation NM_000314(PTEN):c.388C > T;p.Arg130* indicating compound-heterozygous mutation of PTEN in the malignant tumor