Table 1. Characteristics of included studies from Japan.

##	Author	Year	Institution	City	Study cohort	Tissue type	Technique	Total PTC	BRAF+	BRAF rate (%)
1	Kondo T (21)	2007	University of Yamanashi	Yamanashi	n/s	FFPE	Seq	31	13	42
2	Kumagai A (22)	2007	Nagasaki University Hospital	Nagasaki	2003–2006	FNA	PCR-RFLP	14	12	86
3	Takahashi K (23)	2007	Radiation Effects Research Foundation	Hiroshima	2003–2005	FFPE	RFLP	64	38	59
4	Matsuse M (24)	2011	Kuma Hospital	Kobe	n/s	FFPE	Seq	492	388	79
5	Mitsutake N (18)	2015	Fukushima Medical University	Fukushima	2013–2014	Fresh frozen	Seq	67	43	64
6	Xing M (25)	2015	Kanagawa Cancer Center	Yokohama	n/s	Fresh frozen	Seq	49	33	67
7	Nasirden A (26)	2016	Juntendo University Hospital	Tokyo	2009, 2017	FFPE	Seq	144	53	37
8	Vuong HG (27)	2016	Yamanashi Hospital	Yamanashi	2011–2014	FFPE	AS-PCR	67	55	82
9	Oishi N (28)	2017	University of Yamanashi + Kuma Hospital	Yamanashi, Kobe	1991–2013	FFPE	AS-PCR + Seq	172	121	70
10	Bandoh N (29)	2018	Hokuto Hospital	Obihiro	2014–2016	FFPE	Seq	34	27	79

AS-PCR, allele specific-polymerase chain reaction; FFPE, formalin fixed paraffin embedded tissues; FNA, fine needle aspiration; n/s, not specified; PCR-RFLP, polymerase chain reaction-restriction fragment length polymorphism; Seq, sequencing.