MMP9 and breast angiosarcoma: We evaluated the expression of some immune markers not previously studied in the BA children, including leukocyte expression of the MMP-2, MMP-9, TIMP-1, and TIMP-2, frequencies of activated, “suppressor” T cells bearing the glycoprotein-A repetitions predominant protein (GARP)+latency-associated peptide (LAP)+ phenotype, and distribution pattern of the pathogenic Th17.1 and B cell subsets.