Table 1. Cell line characterization.

Cell Line	Vemurafinib sensitive/resistance origin	Main oncogenic events
M229	In vitro naturally sensitive	BRAFV600E homozygous
		AKT1 amplification
		PTEN heterozygous deletion
M229-AR9	In vitro acquired resistance	BRAFV600E homozygous
		AKT1 amplification
		PTEN heterozygous deletion
M238	In vitro naturally sensitive	BRAFV600E heterozygous
		PTEN heterozygous deletion
		CDKN2A homozygous deletion
M238-AR2	In vitro acquired resistance	BRAFV600E heterozygous
		PTEN heterozygous deletion
		CDKN2A homozygous deletion
M249	In vitro naturally sensitive	BRAFV600E heterozygous
		PTEN homozygous deletion
M249-AR4	In vitro acquired resistance	BRAFV600E heterozygous
		NRASQ61K heterozygous
		PTEN homozygous deletion
M370	Patient-derived from a cardiac mass with acquired resistance	BRAFV600E heterozygous
M376	Patient-derived from a nodal metastasis with acquired resistance	BRAFV600E heterozygous
		NRASQ61K heterozygous
		PTEN heterozygous deletion
M380	Patient-derived from a subcutaneous mass with natural resistance	BRAFV600E heterozygous
		CDKN2A homozygous deletion
M395	Patient-derived from an adrenal mass with acquired resistance	BRAFV600E homozygous
		CDKN2A homozygous deletion
M233	In vitro naturally resistant	BRAFV600E heterozygous
		AKT1 amplification
		PTEN homozygous deletion
M244	In vitro naturally resistant	NRASQ61K heterozygous
M263	In vitro naturally resistant	BRAFV600E heterozygous