SOX10 Expression by Triple-Negative Breast Cancer: (A) Triple-negative breast cancers can be negative for (B) GATA-3, and, even when they are positive, expression is often weak, overlapping with the “non-specific” expression seen in other tumor types. (C) SOX10 is expressed by 60% of triple-negative cancers, typically in diffuse, strong fashion, which I have found to be complementary to GATA-3 in securing this diagnosis.