To investigate this further, we isolated 1,606 MCSP+ cells from 477 SLNs of 392 patients with melanoma, performed whole-transcriptome amplification (WTA)22,23 and tested 1,026 high-quality single cells (Methods) for the melanoma transcripts (MT) PMEL (gp100), DCT (dopachrome tautomerase) and MLANA (Melan A) (Extended Data Fig. 1a). The gene discussed is PMEL; the disease is melanoma.