Table 2.

Studies on associations between human ABC transporters and esophageal carcinoma in patients.

Level	Gene	Factor	Patients (N)	Association	Significance	Reference
Gene germline	ABCB1	rs1045642-T allele	210 ESCC and EAC NACRT-treated	longer overall survival after cisplatin	p = 0.030	[17]
	ABCB1	rs1045642	31 ESCC	no effect on response and survival	NS	[19]
	ABCB1	rs1045642-T allele	116 ESCC and 146 EAC NACRT-treated	longer overall survival	p = 0.048	[14]
	ABCB1	rs1045642	meta-analysis	putative biomarker of recurrence and survival	LOE IV #	[21]
	ABCB1 **	rs2032582 **	62 ESCC and 62 EAC NACRT-treated	relapse-free and cancer-free survival	p < 0.001 **	[18]
	TAP1	rs1135216-G allele	361 ESCC and 66 controls	higher risk of ESCC	0.018	[22]
	TAP1	rs1135216-AG heterozygote	200 ESCC and 100 controls	higher risk of ESCC	p = 0.035	[23]
	TAP2	rs1800454-AA homozygote	265 ESCC and 357 controls	higher risk of ESCC	p = 0.023	[24]
	ABCC2 *	rs17222723 *	116 ESCC and EAC NACRT-treated	response	p = 0.002 *	[25]
	ABCC3 *	rs2277624 *	116 ESCC and EAC NACRT-treated	response	p = 0.002 *	[25]
Gene somatic	ABCC4	presence of CNV	1048 Chinese Han subjects	higher ESCC risk and poor overall survival	p = 0.001	[26]
	all ABCs	SNV	2046 ESCC and 568 EAC	unknown	unknown	[27]
Epigenetics-miRNA	ABCB1	high miR-296	25 ESCC	poor survival	p < 0.05	[28]
	ABCB1	high miR-483 and miR-214	104 ESCC	poor survival	p < 0.05	[29]
Transcript	ABCB1	expression	46 ESCC	no prognostic role	NS	[30]
	ABCB1	expression	31 EAC NACRT-treated	no prognostic role	NS	[31]
	ABCB1	high expression	40 EAC NACRT-treated	no prognostic role	NS	[32]
	ABCB1	expression	310 ESCC	poor overall survival	p = 0.014	[33]
	ABCB1	expression	54 unspecified EC derived cell lines	↑ after high dose ↓ after low dose radiotherapy	p < 0.05	[34]
	ABCC1	high expression	38 EAC NACRT-treated	longer overall survival and response	p = 0.017/p = 0.007	[35]
	ABCC1	low expression	31 EAC NACRT-treated	response to NACRT	p = 0.041	[31]
	ABCC1	high expression	40 EAC NACRT-treated	no prognostic role	NS	[32]
	ABCC2	high expression	42 ESCC NACRT-treated	poor response to NACT	p = 0.003	[36]
	ABCG2	high expression	33 ESCC	poor survival	p = 0.017	[37]
Protein	ABCB1	high expression	118 EAC and ESCC NACRT-treated	poor cancer-free survival	p = 0.05	[38]
	ABCB2	expression	143 ESCC	correlates with tumor grade and metastasis	p < 0.05	[39]
	ABCC1	high expression	40 EAC NACRT-treated	poor response to chemotherapy	p = 0.036	[32]
	ABCC1	expression	116 ESCC	no prognostic role	NS	[40]
	ABCC1	expression	829 ESCC	no prognostic role	NS	[41]
	ABCC2	high expression	582 ESCC	correlates with tumor grade	p < 0.01	[42]
	ABCC2	expression	81 ESCC	poor overall survival and response to NACRT	p = 0.027/p = 0.003	[36]
	ABCC3	IgA autoantibodies	114 ESCC and 226 controls	diagnostic and predictive biomarker	p < 0.001	[43]
	ABCE1	expression	112 ESCC	correlates with ESCC grade and stage	p < 0.001	[44]
	ABCG2	expression	100 ESCC	poor survival	p = 0.009	[37]
	ABCG2	high expression	110 ESCC	poor overall survival	p = 0.005	[45]

Footnotes: * As part of five-gene (ABCC2, ABCC3, CYP2A6, PPARG, and SLC7A8) predictive panel; ** as part of five-polymorphism (ABCB1, MTHFR, GSTP1, and two in XPC) panel; ^# Cumulative Level Of Evidence [46]. Abbreviations: CNV, copy number variation; EAC, esophageal adenocarcinoma; ESCC, esophageal squamous cell carcinoma; EC, esophageal carcinoma of unspecified type; NACRT, neoadjuvant chemo-radiotherapy; NS, non-significant; SNV, single nucleotide variation.