Analysis of the Molecular Profile of Melanoma Brain Metastases using Immunohistochemistry

Abstract Brain metastases from melanoma represent an advanced and aggressive form of the disease. Understanding their molecular characteristics is crucial for improving diagnosis, prognosis, and treatment. The main objectives of this study were to identify and characterize molecular alterations present in brain metastases from melanoma and to clinically correlate them. The clinical-epidemiological information was anonymously and retrospectively obtained. Brain metastases from melanoma were collected through surgical biopsies, which were processed and analyzed using immunohistochemical markers. A total of 132 samples were initially selected, resulting in 8 samples of metastatic melanoma in the brain region included in this analysis. Regarding the frequency of immunohistochemical markers in brain samples of melanoma metastasis, 75% showed positive BRAF V600R, 62% contained positive SOX10, 37% positive HMB45, and 25% positive Melan-A. Regarding the location, 4 of them were in the frontal lobe, 3 in the parietal lobe, and 1 in the cerebellum. Among the samples, 87.5% originated from the supratentorial region of the brain, while 12.5% came from the infratentorial region. At the time, half of the patients were under 65 years old, with a significant proportion of 25% of individuals being below 40 years old. Moreover, 87.5% had two or more brain lesions at the time of diagnosis. Among the 12.5% that comprised the single lesion group at the time of analysis, the frontal lobe location stands out. The findings indicate heterogeneity among tumors and metastases in different anatomical locations. Further investigations are needed to validate these findings and elucidate their clinical applicability.