What Is an Inherited PTEN Mutation? Cancer Surveillance and Treatment Guidance for Carriers

General Information About Inherited PTEN Mutations

• PTEN (Phosphatase and Tensin Homolog), which regulates cell growth, division, and survival, is a tumor suppressor gene. By controlling intracellular signaling pathways, PTEN prevents cell proliferation and metastasis . It generally inhibits cancer development by suppressing the phosphoinositide-3-kinase (PI3K) pathway.
• In the PTEN gene, mutationscan impair tumor suppression and contribute to tumor development and progression in many cancers.
• In PTEN, germline pathogenic variants (inherited mutations)are associated with the autosomal dominantly inherited PTEN Hamartoma Tumor Syndrome (PHTS) .
• PHTS includes Cowden syndrome, Bannayan–Riley–Ruvalcaba syndrome, and Proteus-like syndrome.
• PHTS encompasses several multisystem disorders involving hamartomatous growths and increases the risks of breast, thyroid, and kidney cancers, and possibly other cancers (endometrial, colorectal, and melanoma).
• Lhermitte–Duclos disease (LDD), a dysplastic gangliocytoma of the cerebellum, is associated with PHTS but is not specific to it.
• For inherited PTEN mutation carriers, the estimated lifetime risk of any cancer is 85-89%. These cancers arise predominantly in adulthood. See below for more specific cancer risks.
• There are no specific recommendations for nonmalignant manifestations of PHTS.
• Childhood manifestations may include macrocephaly, intellectual disability, developmental delay, and autism spectrum disorders.
• Cancer surveillance is not recommended in childhood. Pediatric management guidelines for people with PHTS are addressed separately.

Risks Associated with Inherited PTEN Mutations

Breast Cancer:

• Lifetime cancer risk ≈ 67-85% (in women).
• Average age at diagnosis: 38-46 years.
• Fibrocystic breast disease is common.

Thyroid Cancer:

• Lifetime cancer risk ≈ 6-38% (usually follicular, rarely papillary; medullary cancer risk is not increased).
• Median age at diagnosis: 37 years.
• The risk of other thyroid conditions may reach 75% (multinodular goiter, adenomatous nodules, and follicular adenomas).

Endometrial (Uterine) Cancer:

• Lifetime cancer risk ≈ 2-28%.
• Risk increases in the late 30s and early 40s.
• Benign uterine fibroids are common.

Kidney (Renal) Cancer:

• Lifetime cancer risk ≈ 2-34% (mainly papillary).
• Risk increases in the late 40s.

Gastrointestinal (Stomach and Bowel) Cancer:

• Lifetime colorectal cancer risk ≈ 9-20%.
• Average age at diagnosis: 44-58 years.
• Polyps are common and may show diverse histology throughout the stomach and colon (hamartomatous, hyperplastic, adenomatous, inflammatory, and ganglioneuromas).
• Polyps may present acutely in childhood with rectal bleeding (due to intussusception).

Skin Cancer:

• For melanoma, lifetime risk is ≈ 0-6%.
• Numerous nonmalignant lesions may occur.

Management Recommendations:

Surveillance:

• Breast: Annual imaging at ages 30-50 with MRI and annual mammography from age 40.
• Thyroid: Annual ultrasound from age 18. Earlier surveillance may be considered if thyroid cancer occurred in the family before 16 or if clinically indicated.
• Kidney: Ultrasound every 2 years from age 40.
• Colorectal: Baseline assessment at ages 35-40 with colonoscopy to determine polyp burden. Polyps should be monitored as needed. If results are normal, follow standard age-appropriate screening guidelines. Earlier colonoscopy may be considered when clinically indicated.
• Skin: A baseline examination by a dermatologist from age 30, with follow-up as needed.
• Gynecology: Routine endometrial surveillance is not recommended, although it may be considered within clinical studies. Patients should be informed about important gynecological symptoms such as postmenopausal or irregular bleeding.
• Brain: MRI is recommended to assess for Lhermitte–Duclos disease if symptoms such as ataxia or increased intracranial pressure occur.

Chemoprevention:

No data support chemoprevention in PTEN Hamartoma Tumor Syndrome (PHTS), such as tamoxifen for breast cancer or aspirin for bowel polyps/cancer.

Surgery:

• Breast-conserving surgery or bilateral risk-reducing mastectomy may be considered individually. However, it is generally not recommended below age 30 or above 60. Informed consent and shared decision-making are important.
• There is no evidence regarding risk-reducing hysterectomy.

Lifestyle Advice:

• Patients should receive detailed information about important symptoms of the cancers listed above. In particular, childhood symptoms such as bowel obstruction (intussusception) or thyroid cancer should be recognized and addressed promptly.
• Patients should be informed about the cancer-risk benefits of stopping smoking, reducing alcohol, maintaining a healthy weight, and staying physically active.

Family Issues:

• At-risk relatives should be referred to clinical genetics services for genetic testing.
• Referral to clinical genetics services is recommended to discuss reproductive options.

*

Related topic: Changing Genetic Inheritance Is Possible: A Way to Prevent Hereditary Cancer