TABLE 2

Phospho-extracellular signal-regulated kinase (pERK) and BRAF/NRAS/MAP2K1 mutation status in the 26 analysed pulmonary Langerhans cell histiocytosis lesions

Patient	CD1a cells	pERK status^#	*BRAF* V600 status			MAP2K1 status	*NRAS* Q61 status
Patient	CD1a cells	pERK status^#	Genotype^¶	Mutant allele frequency	VE1	Genotype	Genotype^¶	Mutant allele frequency
1	30	+	V600E	36.7	+	WT	WT	0
2	40	2+	V600E	20.7	+	WT	WT	0
3	20	+	V600E	7.4	+	WT	Q61K	4.0
4	80	+++	V600E	8.9	+	WT	Q61K	5.2
5	80	–/+	V600E	29.6	+	WT	WT	0
6	50	–/+	V600E	16.1	+	WT	WT	0
7	20	++	V600E	9.2	+	WT	Q61R	39.1
8	50	+	V600E	7.6	–	WT	WT	0
9	20	+	V600E	19.4	+	WT	Q61K	2.0
10	10	–/+	V600E	12.0	+	WT	Q61R	1.0
11	40	+	V600E	16.3	–	WT	WT	0
12	30	+	V600E	27.9	+	WT	Q61R	1.0
13	50	++	V600E	10.5	+	WT	Q61K	8.3
14	10	+	WT	0	–	C121S	WT	0
15	50	+	WT	0	–	WT	WT	0
16	30	+/++	WT	0	–	WT	WT	0
17	50	++	WT	0	–	WT	WT	0
18	30	+	WT	0	–	WT	Q61K	4.0
19	40	+	WT	0	–	C121S	WT	0
20	10	NA	WT	0	NA	WT	WT	0
21	20	–/+	WT	0	+	WT	WT	0
22	10	NA	WT	0	–	WT	Q61K	1.0
23	10	NA	WT	0	NA	WT	Q61K	7.9
24	30	+	WT	0	–	C121S	WT	0
25	10	++	WT	0	–	WT	Q61K	3.0
26	30	+	WT	0	–	WT	WT	0

Data are presented as %, unless otherwise stated. WT: wild-type; NA: not available. ^#: two BRAFV^600E-mutated melanomas (both positive for VE1 immunostaining) were used as positive controls (these samples were scored ++ and +++, respectively, for pERK immunostaining); ^¶: BRAF and NRAS genotyping was performed by both pyrosequencing and E-ice-COLD-PCR (enhanced improved and complete enrichment coamplification at lower denaturation temperature PCR).