Revisiting the clinical and biologic relevance of partial PTEN loss in melanoma

The extent of PTEN loss that confers clinical and biological impact in melanoma is unclear. We evaluated the clinical and biologic relevance of PTEN dosage in melanoma, and tested the postulate that partial PTEN loss is due to epigenetic mechanisms. PTEN expression was assessed by immunohistochemistry in a stage III melanoma cohort (n=190) with prospective follow up. 21/190 (11%) of tumors had strong PTEN expression, 51/190 (27%) had intermediate PTEN, 44/190 (23%) had weak PTEN, and 74/190 (39%) had absent PTEN.