Melanoma is the third most common brain metastasis cause in the United States as it has a relatively high susceptibility
to metastasize to the central nervous system. Among the different origins for brain metastasis, those originating
from primary gastric melanomas are extremely rare. Here, we compare protein profiles obtained from formalin-fixed paraffin-
embedded (FFPE) tissues of a primary gastric melanoma with its meningeal metastasis. For this, the contents of a
microscope slide were scraped and ultimately analyzed by nano-chromatography coupled online with tandem mass spectrometry
using an Orbitrap XL. Our results disclose 184 proteins uniquely identified in the primary gastric melanoma, 304
in the meningeal metastasis, and 177 in common. Notably, we indentified several enzymes related to changes in the metabolism
that are linked to producing energy by elevated rates of glycolysis in a process called the Warburg effect.
Moreover, we show that our FFPE proteomic approach allowed identification of key biological markers such as the S100
protein that we further validated by immunohistochemistry for both, the primary and metastatic tumor samples. That said,
we demonstrated a powerful strategy to retrospectively mine data for aiding in the understanding of metastasis, biomarker
discovery, and ultimately, diseases. To our knowledge, these results disclose for the first time a comparison of the proteomic
profiles of gastric melanoma and its corresponding meningeal metastasis.