Biomarkers in Barrett’s esophagus and esophageal adenocarcinoma: Predictors of progression and prognosis

Table 1 Summary of the most promising biomarkers for identifying patients with Barrett’s esophagus at high risk of developing esophageal adenocarcinoma

Surveillance biomarker	Highest EDRN stage	Study size (n)1	Findings	Statistical significance	Ref.
HGD	4	15	Progression to EA in 4 out of 15 patients with unifocal HGD	RR not available	[29]
		485	20 patients with HGD treated with omeprazole only developed EA	RR not available	[30]
		327	33 out of 76 patients with HGD developed EA	RR 28 (95% CI: 13-63)	[31]
		1099	12 out of 75 patients with HGD developed EA	RR 12.1 (95% CI: 5-29.4)	[32]
Aneuploidy and LOH (Reid Panel)	4	243	Panel of biomarkers (LOH of 17p and 9p and DNA abnormalities) can best predict progression to EA	RR 38.7 (95% CI: 10.8-138.5)	[33]
			LOH of 17p alone	RR 10.6 (95% CI: 5.2-21.3)
			LOH of 9p alone	RR 2.6 (95% CI: 1.1- 6.0)
			Aneuploidy alone	RR 8.5 (95% CI: 4.3-17.0)
			Tetraploidy alone	RR 8.8 (95% CI: 4.3-17.7)
p53 positivity by immunohistochemistry	3	164	Diffuse or intense TP53 staining elevated in patients who developed EA compared to controls	OR 11.7 (95% CI: 1.93-71.4)	[34]
		48	3 out of 5 patients with low grade dysplasia who progressed to high grade dysplasia had positive p53	RR not available	[35]
Mcm2	3	27	Ectopic luminal surface expression predictive of progression to HGD or EA	OR 136 (95% CI: 7.5-2464)	[36]
Cyclin A	3	48	Ectopic luminal surface expression predictive of progression to HGD or EA	OR 7.6 (95% CI: 1.6-37)	[37]
Methylation markers	3	53	Hypermethylation of p16 (cyclin-dependent kinase inhibitor 2A), RUNX3 (Runt-related transcription factor 3) and HPP1 (transmembrane protein with EGF-like and two follistatin-like domain 2) associated with an increased risk of progression to high grade dysplasia or EA	OR 1.74 (95% CI: 1.33-2.2), 1.80 (95% CI: 1.08-2.81) and 1.77 (95% CI: 1.06-2.81), respectively	[38]
		195	A 8 gene methylation panel in combination with age could predict half of progressors to HGD or EA who would not have been diagnosed without the use of the panel	RR not available	[39]

¹Study size includes all patients in study and findings are extracted when relevant. Mcm2: Minichromosome maintenance protein 2; EA: Esophageal adenocarcinoma; HGD: High-grade dysplasia; LOH: Loss of heterozygosity; EDRN: Early Detection Research Network; RR: Relative risk; OR: Odds ratio; CI: Confidence interval.

Table 2 Summary of the biomarkers and the prognostic impact in esophageal adenocarcinoma

Category of cell alteration	Biomarker	Sample size (n)	Endpoint	Findings	Statistical significance	Ref.
Self sufficiency in growth signals	Cyclin D	124	Survival	2 of 3 genotypes confers a poorer overall survival	P = 0.0003	[77]
	EGFR	103	Survival	Expression showed a trend towards a correlation with poorer overall survival	P = 0.07	[78]
		75	Survival	Decreased expression correlated with poorer survival on univariate analysis only	P = 0.034	[79]
	Ki-67	59	Survival	Low levels (< 10%) of staining correlated with poorer survival	HR: 3.9, P = 0.02	[80]
	Her2/neu	63	Survival	Amplification detected by FISH correlated with poorer survival	P = 0.03	[81,82]
	TGF-α	61	Survival	Low levels significantly correlated with cancer specific death	P = 0.03	[83]
		87	Tumor progression, lymph node metastasis	High levels significantly correlated with:		[84]
				Tumor progression	P = 0.025
				Lymph node metastasis	P < 0.05
Insensitivity to growth inhibitory (antigrowth) signals	TGF-β1	123	Survival	Overexpression correlated with poorer survival on univariate analysis only	P = 0.0255	[85]
		57	Survival	High plasma levels correlated with poorer overall survival	P = 0.0317	[86]
	APC	52	Survival	High plasma levels of methylation of APC associated with poorer survival	P = 0.016	[87]
	P21	30	Survival	Alteration in expression after chemotherapy correlated with better survival	P = 0.011	[88,89]
Evasion of programmed cell death (apoptosis)	P53	30	Survival	Alteration in expression after chemotherapy correlated with better survival	P = 0.011	[88]
	Bcl-2	35	Survival	Expression correlated with poorer survival	P = 0.03	[90]
	COX-2	100	T-stage, N-stage, tumor recurrence and survival	Higher levels expression correlated with:		[91]
				Higher T-stage,	P = 0.008
				Higher N-stage,	P = 0.049
				Increased risk of tumor recurrence	P = 0.01
				Poor survival	P < 0.001
		20	Survival	Strong staining correlated with poorer survival	P = 0.03	[92]
		145	Distant metastasis, local recurrence and survival	Strong staining correlated with:		[93]
				Distant metastasis	P = 0.02
				Local recurrence	P = 0.05
				Poorer survival	P = 0.002
	NF-κB	43	Survival	Activated NF-κB predictive of:		[94]
				Poorer disease free survival	P = 0.010
				Poorer overall survival	P = 0.015
Limitless replicative potential	Telomerase	46	Survival	Higher telomere-length ratio shown to be an independent poor prognostic factor	P < 0.02	[95]
Sustained angiogenesis	CD105	75	Survival, angiolymphatic invasion, lymph node metastasis and tumor stage and distant metastasis	Significant correlation between expression and:		[96]
				Poorer survival	P < 0.01
				Presence of angiolymphatic invasion	P < 0.05
				More lymph node metastasis	P < 0.01
				Higher tumor stage	P < 0.001
				More distant metastasis	P < 0.01
	VEGF	75	Survival, angiolymphatic invasion, lymph node metastasis, stage of tumor and distant metastasis	Significant correlation between high expression and:		[96]
				Poorer survival	P < 0.01
				Presence of angiolymphatic invasion	P < 0.05
				More lymph node metastasis	P < 0.01
				Higher stage of tumor	P < 0.01
				More distant metastasis	P < 0.01
Tissue invasion and metastasis	Cadherin	59	Survival	Reduced level correlated with poorer overall survival	HR: 3.3, P = 0.05	[80]
	uPA	54	Survival	High uPA correlated with poorer survival	P = 0.0002	[97]
	TIMP	24	Survival and disease stage	Reduction of expression correlated with poorer overall survival and higher disease stage	P = 0.007	[98]
					P = 0.046
Others	Promoter hypermethylation	41	Survival and tumor recurrence	Earlier tumor recurrence and poorer overall survival if > 50% of gene profile methylated	P = 0.05	[99]
					P = 0.04
		84	Differentiation	Hypermethylation of MGMT (Methylated-DNA-protein-cysteine methyltransferase) gene correlated with:	P = 0.0079	[100]
				Higher tumor differentiation

EGFR: Epidermal growth factor receptor; Her2/neu: Human EGFR2; TGF: Transforming growth factor; APC: Adenomatosis polyposis coli; P21: Cyclin-dependent kinase inhibitor 1; Bcl-2: B-cell lymphoma 2; COX-2: Cyclooxygenase-2; NF-κB: Nuclear factor-κB; CD105: Endoglin; VEGF: Vascular endothelial growth factor; uPA: Urokinase-type plasminogen activator; TIMP: Tissue inhibitor of metalloproteinase.

Table 3 Summary of the molecular signatures discovered by microarray technology and latest methods used to correlate molecular alterations and prognosis in patients with esophageal adenocarcinoma

Method	Sample size (n)	Outcome	Findings	Statistical significance	External validation	Ref.
Oligonucleotide cRNA microarray	75	Survival	A 4-gene signature prognosticated patients	P = 0.0001	Yes	[113]
	77	Lymphatic spread	Created a gene signature predicting lymph node metastasis	Argininosuccinate synthetase expression (ASS) (P = 0.048)	No	[114]
	19	Chemotherapy response	Unsupervised hierarchical clustering divided patients into 2 groups, one of which responded to preoperative chemotherapy	Not statistically significant	No	[115,116]
	47	Chemotherapy response	86 genes dysregulated	P < 0.001	No	[117]
			Ephrin B3 expression associated with chemotherapy response, tumor grading and stage
Oligonucleotide cDNA microarray	46	Chemotherapy response	Gene signature not predictive in adenocarcinoma of esophagus	Not statistically significant	No	[118]
Proteomic analysis	34	Chemotherapy response	HSP27 expression associated with response to chemotherapy	P < 0.05	No	[119]
Single nucleotide polymorphism	210	Survival and recurrence	5 polymorphisms in 3 genes associated with longer recurrence free survival and reduced recurrence	P = 0.004	No	[120]
microRNAs analysis	96	Survival	Low miR-375 levels associated with worse survival	P = 0.002	No	[121]
Multiplex ligation-dependent probe amplification	33	Survival	Patients with more than 12 chromosomal aberrations had a poorer outcome than patients with < 12	P = 0.014	No	[122]