Sirolimus to Treat Cowden Syndrome and Other PTEN Hamartomatous Tumor Syndromes

Background: People with phosphatase and tensin homolog deleted on chromosome 10 (PTEN) hamartomatous tumor syndromes (PHTS) have a mutation in one of their genes called PTEN that can lead to benign tumors called hamartomas throughout the body. This puts them at increased risk for breast, thyroid and endometrial cancer. People with a PTEN mutation have increased activity of proteins such as protein kinase B (AKT) and mammalian target of rapamycin (mTOR), which may be responsible for tumor growth and their increased risk of these cancers. Experiments show that a drug called sirolimus, which is used to prevent the immune system from rejecting transplanted organs, can inhibit cancer cell growth by blocking the mTOR protein. Objectives: To test the ability of sirolimus to decrease the activity of proteins that are regulated by mTOR in both benign and cancerous tumor tissue. Eligibility: People 18 years of age and older with Cowden syndrome or other PHTS. Design: Sirolimus treatment. Patients take sirolimus once a day in 28-day treatment cycles. Patients who do not have cancer take the drug for a total of two cycles (56 days) unless they develop unacceptable side effects. Those who have cancer may continue sirolimus beyond cycle 2 until their disease worsens or they develop unacceptable side effects. Evaluations. Patients come to the clinic for a history and physical examination on day 1 of every treatment cycle, then every month for the first two months off therapy, and then at 6 and 12 months. In addition, they have the following procedures:

• Positron emission tomography (PET) scan and neuropsychological testing before starting treatment.
• Clinical photography (photographic documentation of skin lesions) before starting treatment. Patients who do not have cancer have repeat photography at 2 and 8 weeks and then, if the lesions shrink or go away while on therapy, again every month for the first 2 months off sirolimus, then at 6 months and 1 year. Patients who have cancer and continue treatment beyond 8 weeks have repeat photography every 8 weeks while on the study.
• Digital dermoscopy (skin lesion examination using a high resolution camera). This is done at the same intervals as clinical photography.
• Multiple biopsies of the skin and lower intestine, and possibly the tumor in patients with cancer, before starting treatment, at 2 weeks of treatment and at 8 weeks of treatment.
• Blood and urine tests every week while on treatment for the first two cycles, then every 4 weeks for patients who continue treatment beyond two cycles.
• Imaging studies, such as computerized tomography (CT), ultrasound or magnetic resonance imaging (MRI) in patients with cancer before starting treatment and again every two cycles to monitor the tumor size and location.