Table 2.

Comparison of different studies about K-ras gene status in CRC all around the world

Study	Year	Method	Sample size	Mutation prevalence (%)	Most common substitution
Iraq2	2012	PCRReverse hybridization to oligospecific probes	50	48	12G>T
		Codon 12, 13
Saudi Arabia11	2011	PCRsequencing	46	32	12G>A
		Codon 12, 13
Turkey12	2013	Codon 12, 13	145	37.9	-
Jordan13	2012	RTPCRbased assay Sanger sequencing	100	44	12G>A
		Codon 12, 13
India14	2009	PCRsequencing	53	22.64	12G>A
		Codon 12, 13
Japan15	2000	PCRsequencing	18	50	12G>T
		Only Codon 12
Thailand16	2013	PCRsequencing	200	23	12G>A
		codon 12, 13 and 61
China17	2010	PCRsequencing	101	32.7	12G>A
		codon 12, 13, 61
Korea18	2010	PCRsequencing	92	28.3	12G>A
		Codon 12, 13
Italy19	2011	PCRsequencing (fluorescencebased)	478	30	12G>A
		Codon12, 13, 61
UK20	2013	PCRsequencing	69	49.3 (46.4)	12G>A
		Codon12, 13, 61
Germany21	2009	PCRsequencing	1018	39.3	12G>A
		Codon 12, 13
Slovenia22	2010	RTPCR	302	45.5	12G>A
		Codon 12, 13
USA23	2013	PCRsequencing	171	31.6	12G>T
		Codon 12, 13
Australia24	2013	PCRsequencing	776	28	-
		Codon 12, 13
Tunisia25	2012	PCR sequencing	52	23.07	-
		Codon 12, 13
Moroco26	2010	PCRmelting and direct sequencing	62	29	-
		Codon 12, 13
Current study	2013	PCRsequencing	100	32	12G>C