Immunoexpression of endoglin in brain metastasis secondary to malignant melanoma: evaluation of angiogenesis and comparison with brain metastasis secondary to breast and lung carcinomas.

Brain metastases are linked to poor prognosis. After carcinomas of the lung and breast, malignant melanomas (MM) are the next type of neoplasm with the higher metastatic dissemination involving the central nervous system and that has the worst prognosis after metastasis has been diagnosed. Angiogenesis has been linked to tumor growth and metastasis. Among the immunomarkers of angiogenesis, endoglin (CD105) is the most specific antibody, since it is a marker for tumor endothelium, and expression of CD105 has been observed to be associated with prognosis in several types of tumor, which is not always observed in melanomas. This study investigated angiogenesis in brain metastasis secondary to malignant melanomas and compared these with brain metastasis secondary to carcinomas of the lung and breast, through expression of CD105 (endoglin). The study investigated 93 cases of brain metastasis secondary to MM (33) and carcinomas of the lung (31) and breast (29), assessing endoglin immunoexpression, number of microvessels and diameter of tumor vessels. Tumor microvessels were counted using a modified version of the Chalkley technique. The observed difference between MM and breast carcinoma was statistically significant (P = 0.026). The difference between MM and lung carcinoma was not significant (P = 0.218). Vascular diameter observation revealed no statistical difference between the vascular size of neoplastic vessels in MM and in breast and lung carcinomas. Of the tumors investigated here, malignant melanomas were shown to have the lowest number of microvessels and had intermediate tumor vessel diameter as compared to carcinomas of the lungs and breast. Such results were not expected to be found in neoplasms such as melanomas that, besides presenting high dissemination capacity, have a high index of hemorrhage secondary to brain metastasis.