{"entity":{"id":"pten-loss","kind":"term","name":"PTEN loss","aka":["PTEN","PTEN mutation","PTEN deletion","PTEN-deficient","PTEN-null","PTEN alteration","PTEN immunohistochemistry","PTEN loss by IHC","PTEN-altered","PIK3CA/AKT1/PTEN alterations","PI3K pathway alteration","AKT pathway alteration","Cowden syndrome","PTEN hamartoma tumour syndrome"],"tldr":"PTEN is the brake on the PI3K/AKT growth pathway; when a tumour deletes or mutates it (seen as a lost stain or on sequencing) the pathway runs unopposed. In hormone-treated breast cancer PTEN loss is one of the three changes that qualify a woman for capivasertib, in prostate cancer it marks aggressive disease, and in endometrial cancer it is almost universal in the NSMP group.","summary":"What is measured: loss of the PTEN phosphatase, by deletion, mutation or silencing. How: immunohistochemistry (loss in tumour cells with retained staining in stroma, validated in prostate cancer), next-generation sequencing of tissue or plasma for mutations and homozygous deletion, FISH for 10q23; germline PTEN testing for Cowden syndrome (macrocephaly, hamartomas, breast, thyroid and endometrial cancer risk). Frequencies: 50 to 80 percent of endometrial cancers (NSMP and mismatch repair-deficient classes), about 40 percent of glioblastomas, 20 percent of localised and 40 to 50 percent of castration-resistant prostate cancers (often with TP53 and RB1 loss), 5 to 7 percent of hormone receptor-positive breast cancers (PIK3CA, AKT1 and PTEN together about half), and melanoma and triple-negative breast cancer. What a result changes: in HR-positive, HER2-negative breast cancer after endocrine progression, a PIK3CA, AKT1 or PTEN alteration qualifies for capivasertib with fulvestrant (CAPItello-291, progression-free survival 7.3 against 3.1 months in the altered group); in prostate cancer PTEN loss carries an adverse prognosis, ipatasertib with abiraterone improved radiographic progression-free survival in PTEN-loss tumours in IPATential150 without approval, and capivasertib with abiraterone reported a benefit in CAPItello-281; in endometrial cancer it underpins mTOR and PI3K inhibitor trials and everolimus with letrozole; a germline finding sets lifelong surveillance. Where it matters: HR-positive breast cancer, metastatic prostate cancer, NSMP endometrial cancer and chromophobe RCC.","asOf":"2026-09-17","wikipedia":"https://en.wikipedia.org/wiki/PTEN_(gene)","links":[{"label":"Wikipedia","url":"https://en.wikipedia.org/wiki/PTEN_(gene)"}],"tags":[],"related":["pik3ca","akt","capivasertib","alpelisib","inavolisib","everolimus","ihc","ngs","hereditary-cancer-syndromes","nsmp"],"cancers":["breast-hr-positive","hr-positive-metastatic-post-cdk46","prostate-mhspc","prostate-mcrpc","endometrial-nsmp","chromophobe-rcc"],"sections":[],"technologies":[],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"category":"Biomarkers"},"route":"/terms/pten-loss/","neighbours":{"target":[{"id":"akt","kind":"target","name":"AKT","route":"/targets/akt/"},{"id":"pik3ca","kind":"target","name":"PIK3CA / PI3K-alpha","route":"/targets/pik3ca/"}],"drug":[{"id":"alpelisib","kind":"drug","name":"Alpelisib","route":"/drugs/alpelisib/"},{"id":"capivasertib","kind":"drug","name":"Capivasertib","route":"/drugs/capivasertib/"},{"id":"everolimus","kind":"drug","name":"Everolimus","route":"/drugs/everolimus/"},{"id":"inavolisib","kind":"drug","name":"Inavolisib","route":"/drugs/inavolisib/"}],"term":[{"id":"hereditary-cancer-syndromes","kind":"term","name":"Hereditary cancer syndromes","route":"/terms/hereditary-cancer-syndromes/"},{"id":"ihc","kind":"term","name":"Immunohistochemistry (IHC)","route":"/terms/ihc/"},{"id":"ngs","kind":"term","name":"Next-generation sequencing (NGS)","route":"/terms/ngs/"},{"id":"nsmp","kind":"term","name":"No specific molecular profile (NSMP) endometrial cancer","route":"/terms/nsmp/"}],"cancer":[{"id":"chromophobe-rcc","kind":"cancer","name":"Chromophobe renal cell carcinoma","route":"/cancers/chromophobe-rcc/"},{"id":"endometrial-nsmp","kind":"cancer","name":"Endometrial cancer with no specific molecular profile","route":"/cancers/endometrial-nsmp/"},{"id":"breast-hr-positive","kind":"cancer","name":"HR-positive / HER2-negative breast cancer","route":"/cancers/breast-hr-positive/"},{"id":"hr-positive-metastatic-post-cdk46","kind":"cancer","name":"HR-positive metastatic breast cancer after CDK4/6 inhibitors","route":"/cancers/hr-positive-metastatic-post-cdk46/"},{"id":"prostate-mcrpc","kind":"cancer","name":"Metastatic castration-resistant prostate cancer","route":"/cancers/prostate-mcrpc/"},{"id":"prostate-mhspc","kind":"cancer","name":"Metastatic hormone-sensitive prostate cancer","route":"/cancers/prostate-mhspc/"},{"id":"prostate-nmcrpc","kind":"cancer","name":"Non-metastatic castration-resistant prostate cancer","route":"/cancers/prostate-nmcrpc/"}]}}