Activating BRAF (V-raf murine sarcoma viral oncogene homolog B) mutations occur in approximately 5% to 10% of patients with metastatic colorectal cancer, mostly V600E mutation, and it is associated with distinct clinical and pathological features.
Histiocytic sarcoma exhibited the highest rate of BRAF(V600E) (62.5%, five of eight), followed by Langerhans cell tumours (25%, seven of 28), FDC sarcoma (18.5%, five of 27) and giant cell tumour (6.7%, two of 30).
To explore the mutation frequencies of BRAF(V600E) (V-raf murine sarcoma virus oncogene homolog B1) and NRAS (neuroblastoma ras viral oncogene homolog) codon 61 in CMNs of Chinese, we selected 55 paraffin-embedded tissue blocks, including 37 cases of medium CMNs (1.5-20cm) and 18 cases of giant CMNs (>20 cm).