While melanoma and thyroid carcinoma show the highest prevalence of <i>BRAF</i> mutations, followed by colorectal and non-small cell lung cancer in terms of absolute number of patients harboring <i>BRAF</i> mutations worldwide, notably high mutation frequencies were identified in rare malignancies, including hairy-cell leukemia, ganglioglioma, and serous borderline ovarian tumors. This evidence concerns the gene BRAF and borderline ovarian serous tumor.