Background: Mesothelin is overexpressed in several malignancies and is purportedly a specific marker of malignant transformation. In this pilot study, we investigated whether tissue and serum mesothelin are potential markers of neoplastic progression in Barrett's esophagus (BE) and in esophageal adenocarcinoma (EAC).
Methods: Mesothelin expression was retrospectively evaluated in normal, BE, and EAC tissue from surgically resected esophageal specimens (n = 125). In addition, soluble mesothelin-related peptide (SMRP) levels were measured in serum.
Results: Normal esophageal mucosa did not express mesothelin. BE tissue with high-grade dysplasia specifically expressed mesothelin, whereas BE tissue with low-grade or without dysplasia did not. Fifty-seven (46%) EAC tumors were positive for mesothelin. EAC tumors with BE expressed mesothelin more often than those without BE (58% vs. 35%, P = 0.01). SMRP levels were elevated in 70% of EAC patients (mean = 0.89 nmol/L; range: 0.03-3.77 nmol/L), but not in patients with acid reflux and/or BE.
Conclusions: Mesothelin is commonly expressed in BE-associated EAC. On the basis of this pilot study, a prospective study is under way to evaluate tissue and serum mesothelin which are potential markers of neoplastic progression in BE and in EAC (NCT01393483).
Impact: Current surveillance methods in Barrett's esophagus are invasive and neither cost-effective nor sensitive. This pilot study suggests that serum mesothelin is a marker of neoplastic transformation in BE and may provide a noninvasive method to improve identification of malignant transformation.