Table 5. The trends of BRAF mutations prevalence of micro PTCs from individual institutions.

Country	City (State)	Institution (Reference)	Prevalence of BRAF mutations in micro PTCs
			Period 1	Period 2	Period 3	Period 4	P
US	Pittsburgh (PA)	Univ. of Pittsburgh [14]	1974-1985 10/31(32.3%) FMCA	1990-1992 3/16(18.8%) FMCA	2000 4/17 (23.5%) FMCA	2009 19/50(38%) FMCA	NS
Poland	Kielce	Holycross Cancer Center [21]	2000-2004 45/90 (50%) Three methods a	2005-2009 104/147 (70.7) Three methods a	2010-2013 147/203 (72.4) Three methodsa		0.001 b
Korea	Seoul	Samsung Medical Centre [26, 27]	2008-2009 253/396(63.9%) DS	2010-2011 97/128(75.8%) DS			0.013
China	Tianjin	Tianjin Medical Univ. Cancer Hospital [24, 25]	2001-2010 392/977(40.1%) DS	2013-2014 1244/1984(62.7%) DS			<0.001

Abbreviations: NS, not significant; DS, direct sequencing; FMCA, fluorescent melting curve analysis

^a All analyses that were performed prior to 2013 by DS and allele-specific PCR (AS-PCR) were verified by quantitative Real time PCR (qPCR). In total, the authors used qPCR to analyze BRAF mutations in 705/723 PTCs (97.5%). The majority of samples were tested using the three methods (DS, AS-PCR and qPCR).

^b P value for trend adjusted for age and sex