Elevated Lactic Acid Levels in the Aqueous Humor May Be an Indicator of Uveal Melanoma

To determine if aqueous humor lactic acid levels, a surrogate marker for tumor cell metabolic activity, are elevated in uveal melanoma (UM) and whether L-lactate levels correlate with clinical, pathologic, and molecular tumor characteristics.

Case-control study.

Eyes with UM and control eyes undergoing cataract surgery.

L-Lactate levels were measured from aqueous humor taken at the time of enucleation for UM (n = 34) or controls (n = 13). Twenty-three (68%) UM patients were followed for at least 5 years. Clinical information was gathered by retrospective chart review. Tumor samples were profiled by RT-qPCR and factor analysis to emulate prognostic classification.

Aqueous humor lactate levels.

Aqueous L-lactate concentration in UM eyes was higher than controls (P < .01). The L-lactate concentration correlated with increasing mitotic activity on pathologic examination (P = .02), but not with tumor size, prior brachytherapy, predominant histologic cell type, or metastasis. L-Lactate levels did not correlate with gene expression profile.

L-Lactate levels in aqueous samples from patients with uveal melanoma were higher than controls, which lays the foundation for future studies into whether this may be helpful for diagnosing suspicious uveal lesions.