Melanoma-specific expression of the tumor suppressor proteins p16 and PTEN is a favorable prognostic factor in established melanoma brain metastases

PTEN and p16 frequently undergo (epi)genetic aberrations in melanoma resulting in decreased, or absent, protein levels. We investigated the prognostic significance of these tumor suppressor genes in melanoma brain metastases (MBMs). Immunohistochemical analysis was performed on archived tissue sections from craniotomies. Expression of PTEN and p16 was semiquantitatively scored (0–3 scale) in melanoma cells, glia, TILs, and endothelial cells of tumor-associated vessels and was compared among the different brain tumor cell compartments. Overall survival (OS) analysis was performed according to PTEN and p16 protein expression in melanoma cells. 58 patients (median age 56, 37 male) underwent craniotomy for MBMs before February 2014. The OS of patients with decreased, or absent, protein expression (0, 1+) of PTEN and p16 in melanoma cells was significantly shorter compared to that of patients with high (2+, 3+) expression (median OS 2.40 vs. 10.75 months and 4.1 vs. 8.1 months, respectively; Gehan-Breslow-Wilcoxon test P = 0.026 and P = 0.037, respectively). PTEN and p16 protein expression were significantly lower in TILs compared to melanoma cells (Mann–Whitney test P = 0.023 and P 
Source: Melanoma Research - Category: Cancer & Oncology Tags: Short Communication: Translational Research Source Type: research