Debate about TGFBR1 and the susceptibility to colorectal cancer

Table 1 Main characteristics of the studies published on allele-specific expression of transforming growth factor β receptor 1 and colorectal cancer risk

Study	Majority population	Sample	Method	Allelic markers	Informative cases/controls	ASE (binary) cases/controls	ASE higher in CRC cases
							Binary	Continuous
Valle et al[73] 2008	Caucasian	Blood	SNaPshot	rs334348	138/105	221.0%/2.9%	Yes	Yes
				rs7871490
				rs334349
				rs1590
Guda et al[74] 2009	Caucasian	Lymph. cell line	Pyroseq	rs868	Familial: 46/17	34.3%/0%	No
		Normal colon		rs334348	Sporadic: 44/0	30%/-
				rs334349
				rs420549
				rs1590
Carvajal-Carmona et al[66] 2010	Caucasian	Lymph. cell line	Genescan	*6A/9A	Familial: 24/45	329.2%/26.7%	No	No
			SNaPshot	rs1590
Pasche et al[75] 2010	Caucasian	Lymph. cell line	SNaPshot	rs334348	74/0	314.9%/-	Yes
				rs7871490
				rs334349
				rs1590
Tomsic et al[76] 2010	Caucasian	Blood	Pyroseq	rs868	1109/125	31.8%/1.6%	No	Yes
				rs334348		246.8%/31.2%
				rs334349
				rs420549
				rs1590
Seguí et al[77] 2011	Caucasian	Normal colon	Pyroseq	rs334349	171/90	30%/2.2%	No	No
	Ashkenazi	Lymphocytes		rs7850895		22.3%/2.2%
				rs420549
				rs1590
Abadie et al[78] 2011	Caucasian	Blood	SNaPshot	rs334348	69/98	30%/0%	No	No
				rs7871490
				rs334349
				rs1590

Lymph. cell line: EBV transformed lymphoblastoid cell line; Pyroseq: Pyrosequencing; Binary: Allele-specific expression (ASE) was considered as a binary trait (ASE vs non-ASE); Continuous: ASE was considered as a continuous/quantitative trait.

¹49 cases were the same as in Valle et al[73], 2008;

²Cut-off values calculations based on own results: Valle et al[73] 2008 and Tomsic et al[76] 2010, ROC analysis; Seguí et al[77] 2011 median controls ± 2 SD;

³Applied the cutoff values established by Valle et al[73] 2008.