Low levels of genetic heterogeneity in matched lymph node metastases from melanoma patients

In our previous experience, a high consistency of BRAF and NRAS muta- tion patterns was observed between primary tumors and lymph node me- tastases in patients with advanced melanoma. Conversely, increasing rates of discrep- ancies in BRAF/NRAS mutation pat- terns were found between primary melanomas and metastases in other sites (brain or, mostly, skin). When the distribution of BRAF/NRAS mutations was evaluated in a larger cohort, the high rate of consistency in sequence variations of these two genes was further confirmed between primary melanomas and lymph node metastases.