A Pilot Study Of Sirolimus (S) In Subjects With Cowden Syndrome (Cs) With Germ-Line Mutations In Pten.

2532 Background: CS is characterized by germline PTEN mutations. Because tumors from CS patients show increased activation of the PI3K/Akt/mTOR pathway, mTOR inhibitor such as S might have activity in such patients. Methods: Eligibility: subjects with germline PTEN mutation who meet international diagnostic criteria for CS, age 18, ECOG PS 0-2, and adequate organ function. Subjects were treated with a 56-day course of daily oral S (2 mg). Objective: Inhibition of the mTOR pathway in benign skin/GI lesion, as assessed by IHC (P-AKT, Total S6, P-S6, P-4E-BP1, score 0-4), changes in benign or malignant tumor by CT/MRI/PET, digital dermoscopy/endoscopy, and changes in cerebellar testing by modified SARA (Neurology 2006). Protocol was amended to allow up to 20 subjects. Results: A total of 18 pts/16 families were enrolled. Median age 42 (range 19-69). Male/Female: 9/9. Involvement in skin, thyroid, GI polyps, breast, CNS, and all of the five organs was observed in 18, 15, 13, 8, 18, 5 subjects, respectively. 7...