Melanocytes in Lymph Nodes: BRAF Is Not the Answer

Sentinel lymph node (SLN) resection is performed to assess tumor stage and prognosis in intermediate-thickness malignant melanomas (MMs). The findings can be difficult to interpret, however, because of the presence of nodal nevi, benign melanocytes found in up to 11% of SLNs that drain MMs. The expression profiles of these two lesion types are overlapping. Investigators explored genetic alteration in nodal nevi as a potential aid to difficult diagnoses.

Researchers studied 26 nodal nevi (from 23 patients with MM and 3 with breast cancer; 2 nodes also contained micrometastatic melanoma) for presence of the thymine-to-adenine missense mutation at nucleotide 1796 of the BRAF gene by LigAmp assay. This technique can detect 1 mutant allele among …