PTEN and Cowden syndrome 1: However, we found that all patients with CS-associated cancers but without any other reported clinical feature of CS (such as macrocephaly or mucocutaneous lesions) were PTEN-wt, i.e., none of them carried an alteration in PTEN. Therefore, the presence of CS-associated cancers should not be criterion to refer a patient for PTEN testing, unless this is accompanied by other features of the disease.