Table 2.

Ancillary studies

Ancillary study	Case 1			Case 2				Case 3
	Primary	First recurrence	Second recurrence	Primary		First recurrence	Second recurrence	Primary
				PTC comp.	MASC comp.			PTC comp.	MASC comp.
S-100	Pos (rare cells)	ND	Pos (rare cells)	Neg	Pos (rare cells)	Pos (focally)	Pos (focally)	Neg	Pos
Mammaglobin	Pos	ND	Pos	Neg	Pos	Pos	pos	Neg	Pos
GCDFP-15	Pos (focally)	ND	Pos (focally)	Neg	Neg	ND	Neg	Neg	Pos (focally)
p63	Pos (focally)	ND	ND	Neg	Pos (focally)	ND	ND	Neg	Pos
PAX8	Pos (weak)	ND	Pos (rare cells)	Pos	Pos (weak)	Pos (weak)	Pos	Pos	Pos (weak)
TTF-1	Neg	Neg	Neg	Pos	Neg	Neg	Neg	Pos	Neg
Thyroglobulin	Neg	Neg	Neg	Pos	Neg	Neg	Neg	Pos	Neg
CK7	Pos	Pos	Pos	Pos	Pos	Pos	Pos	Pos	Pos
CK19	Pos	ND	Pos	Pos (weak)	Pos	Pos	Pos	Pos (weak/very focally)	Pos
Vimentin	Pos	ND	ND	Pos (very focally)	Neg	ND	ND	Pos	Pos
Mucicarmine	Pos	ND	Pos	Neg	Pos	ND	Pos	Neg	Neg
Calponin	ND	ND	Neg	ND	ND	ND	Neg	Neg	Neg
Her-2/Neu	ND	ND	Neg	ND	ND	ND	Neg	Neg	Neg
AR	ND	ND	Neg	ND	ND	ND	Neg	Neg	Neg
Ki-67	1–2% (3/10)	ND	7%	<1%	<1%	ND	2%	<1%	5%
ETV6 FISH	Pos	ND	Pos	Pos	Pos	ND	Pos	Pos	Pos
MSK-IMPACT	ND	ND	ETV6–NTRK3	ETV6–NTRK3	ETV6–NTRK3	ETV6–NTRK3	ND
			ETV6 P214L (c.641C>T)	APC R640W (c.1918C>T)
			KDM5C G496R (c.1486G>C)	HNF1A E619K (c.1855G>A)
			PPP2R1A R182W (c.544C>T)	SYK R22Q (c.65G>A)

ND, not done; PTC, papillary thyroid carcinoma; MASC, mammary analog secretory carcinoma; FISH, fluorescence in situ hybridization.