# PTEN loss

Source: https://onco.cc/terms/pten-loss/  
OnCo record `pten-loss` (Term). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

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.

## Fields

- Kind: Term
- Last checked: 2026-09-17
- Also known as: 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

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/PTEN_(gene)
- Wikipedia: https://en.wikipedia.org/wiki/PTEN_(gene)

## Connected records

- targets: [AKT](https://onco.cc/targets/akt/), [PIK3CA / PI3K-alpha](https://onco.cc/targets/pik3ca/)
- drugs: [Alpelisib](https://onco.cc/drugs/alpelisib/), [Capivasertib](https://onco.cc/drugs/capivasertib/), [Everolimus](https://onco.cc/drugs/everolimus/), [Inavolisib](https://onco.cc/drugs/inavolisib/)
- terms: [Hereditary cancer syndromes](https://onco.cc/terms/hereditary-cancer-syndromes/), [Immunohistochemistry (IHC)](https://onco.cc/terms/ihc/), [Next-generation sequencing (NGS)](https://onco.cc/terms/ngs/), [No specific molecular profile (NSMP) endometrial cancer](https://onco.cc/terms/nsmp/)
- cancers: [Chromophobe renal cell carcinoma](https://onco.cc/cancers/chromophobe-rcc/), [Endometrial cancer with no specific molecular profile](https://onco.cc/cancers/endometrial-nsmp/), [HR-positive / HER2-negative breast cancer](https://onco.cc/cancers/breast-hr-positive/), [HR-positive metastatic breast cancer after CDK4/6 inhibitors](https://onco.cc/cancers/hr-positive-metastatic-post-cdk46/), [Metastatic castration-resistant prostate cancer](https://onco.cc/cancers/prostate-mcrpc/), [Metastatic hormone-sensitive prostate cancer](https://onco.cc/cancers/prostate-mhspc/), [Non-metastatic castration-resistant prostate cancer](https://onco.cc/cancers/prostate-nmcrpc/)

---
JSON: https://onco.cc/api/v1/entities/pten-loss.json