Association of high T-cell immune infiltrate and low hemorrhage in melanoma brain metastases (MBMs) with prolonged survival.

8528 Background: Despite the poor prognosis of patients (pts) with MBM several pts have prolonged survival. We hypothesized that the heterogeneity of BrMM is determined by differences in melanoma biology and its brain microenvironment. Methods: We identified pts who have undergone craniotomy for MBMs. Evaluation entailed complete clinical information, acquisition of archived melanoma brain metastases, histopathologic analysis of hematoxylin and eosin-stained sections (n=101), whole genome expression profiling (WGEP, Illumina DASL) in 29 archived tissues. Results were validated by immunohistochemistry (IHC) or in situ hybridization (ISH). Results: In univariate analysis (log-rank) factors significantly associated with prolonged survival were high immune infiltrate (HII) plus low hemorrhage (hazard ratio, HR, 2.71, p<0.001), present melanin (1.67, p=0.03), and recursive partitioning analysis (RPA) class 1 (0.37, p<0.0001). No association between HII and use of immunotherapy prior to craniotomy was noted. On...