Fig. 1.

Enzymes involved in the synthesis of specific gangliosides in MBM. (A–D). mRNA expression of ST3GAL5 (A), HEXA (B), B4GALNT1 (C), and ST8SIA1 (D) assessed by genomewide exon array in cell lines [melanocytes (n = 3), LNM (n = 40), and MBM (n = 7)]. (E). Negative correlation between ST8SIA1 and B4GALNT1 in cell lines (n = 50). (F). ST8SIA1 mRNA expression ( $2$ ${}^{-(\mathrm{\Delta }\mathrm{\Delta }{C}_{\mathrm{T}})}$ ${}^{-(\mathrm{\Delta }\mathrm{\Delta }{C}_{\text{T}})}$ values) was assessed in cell lines [melanocytes (n = 1), LNM (n = 3), and MBM (n = 4)] by qRT‐PCR. (G). Biosynthesis pathway of the gangliosides (GM3, GM2, GD3, and GD2) and the enzymes (ST3GAL5, ST8SIA1, β4GALNT1, and HEXA) involved are shown. (H–K). Analysis of the phenotypic cell surface expression of GM2 (H), GM3 (I), GD2 (J), and GD3 (K) in LNM (n = 7) and MBM (n = 6) assessed by FACS. Cells were gated for live cell population using 7‐AAD dye and evaluated for GM2‐, GM3‐, GD2‐ and GD3‐positive expression. Box plots represent the distribution of the percentage of live cells expressing GM2, GM3, GD2, and GD3, respectively. (t‐test, *P < 0.05, **P < 0.01).