Liquid Biopsy Proteomics in Ophthalmology

Safety Assessment of Aqueous Humor Liquid Biopsy in Retinoblastoma: A Multicenter Study of 1203 Procedures

PURPOSE

To evaluate the safety profile of aqueous humor (AH) liquid biopsy in pediatric patients with retinoblastoma and retinoblastoma-simulating lesions through a multicenter analysis of paracentesis procedures.

DESIGN

Retrospective multicenter study.

PARTICIPANTS

A total of 1203 paracentesis procedures were performed on 484 eyes of 425 pediatric patients, including 352 patients with retinoblastoma and 73 patients with retinoblastoma-simulating lesions.

METHODS

Medical records were reviewed retrospectively to identify complications from anterior chamber paracentesis performed to obtain AH for liquid biopsy. Procedures were conducted during routine examination under anesthesia. Aqueous humor samples were extracted using a 32-gauge needle and underwent cell-free DNA analysis. Complications were classified as mild, moderate, or severe based on clinical impact and required interventions.

MAIN OUTCOME MEASURES

Incidence and severity of complications related to the paracentesis procedure.

RESULTS

Among 1203 procedures, 1 mild complication was identified, representing an overall complication rate of 0.08%. No moderate or severe complications, including vision, eye loss, extraocular tumor spread, or death, were observed at a median follow-up of 16 months. The procedure demonstrated an excellent safety profile across multiple centers, with no permanent adverse outcomes.

CONCLUSIONS

Aqueous humor liquid biopsy via anterior chamber paracentesis is a safe and well-tolerated procedure in pediatric patients with retinoblastoma when performed by trained ocular surgeons under general anesthesia. This large-scale analysis supports the procedure's use as a minimally invasive diagnostic tool with minimal risk, providing valuable molecular insights for retinoblastoma management. These findings offer reassurance to clinicians and parents regarding the safety of AH liquid biopsy for retinoblastoma.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Advances and Prospects in Liquid Biopsy Techniques for Malignant Tumor Diagnosis and Surveillance

Liquid biopsy technology provides invaluable support for the early diagnosis of tumors and surveillance of disease course by detecting tumor-related biomarkers in bodily fluids. Currently, liquid biopsy techniques are mainly divided into two categories: biomarker and label-free. Biomarker liquid biopsy techniques utilize specific antibodies or probes to identify and isolate target cells, exosomes, or molecules, and these techniques are widely used in clinical practice. However, they have certain limitations including dependence on tumor markers, alterations in cell biological properties, and high cost. In contrast, label-free liquid biopsy techniques directly utilize physical or chemical properties of cells, exosomes, or molecules for detection and isolation. These techniques have the advantage of not needing labeling, not impacting downstream analysis, and low detection cost. However, most are still in the research stage and not yet mature. This review first discusses recent advances in liquid biopsy techniques for early tumor diagnosis and disease surveillance. Several current techniques are described in detail. These techniques exploit differences in biomarkers, size, density, deformability, electrical properties, and chemical composition in tumor components to achieve highly sensitive tumor component identification and separation. Finally, the current research progress is summarized and the future research directions of the field are discussed.

Optimizing ctDNA: An Updated Review of a Promising Clinical Tool for the Management of Uveal Melanoma

Uveal melanoma (UM) is the most common primary malignant intraocular tumor in adults. Distant metastasis is common, affecting around 50% of patients. Prognostic accuracy relies on molecular characterization of tumor tissue. In these patients, however, conventional biopsy can be challenging due to the difficulty of obtaining sufficient tissue for the analysis due to the small tumor size and/or post-brachytherapy shrinkage. An alternative approach is liquid biopsy, a non-invasive technique that allows for real-time monitoring of tumor dynamics. Liquid biopsy plays an increasingly prominent role in precision medicine, providing valuable information on the molecular profile of the tumor and treatment response. Liquid biopsy can facilitate early detection and can be used to monitor progression and recurrence. ctDNA-based tests are particularly promising due to their ease of integration into clinical practice. In this review, we discuss the application of ctDNA in liquid biopsies for UM. More specifically, we explore the emerging technologies in this field and the advantages and disadvantages of using different bodily fluids for liquid biopsy. Finally, we discuss the current barriers to routine clinical use of this technique.

Integrating the analysis of human biopsies using post-translational modifications proteomics

Proteome diversities and their biological functions are significantly amplified by post-translational modifications (PTMs) of proteins. Shotgun proteomics, which does not typically survey PTMs, provides an incomplete picture of the complexity of human biopsies in health and disease. Recent advances in mass spectrometry-based proteomic techniques that enrich and study PTMs are helping to uncover molecular detail from the cellular level to system-wide functions, including how the microbiome impacts human diseases. Protein heterogeneity and disease complexity are challenging factors that make it difficult to characterize and treat disease. The search for clinical biomarkers to characterize disease mechanisms and complexity related to patient diagnoses and treatment has proven challenging. Knowledge of PTMs is fundamentally lacking. Characterization of complex human samples that clarify the role of PTMs and the microbiome in human diseases will result in new discoveries. This review highlights the key role of proteomic techniques used to characterize unknown biological functions of PTMs derived from complex human biopsies. Through the integration of diverse methods used to profile PTMs, this review explores the genetic regulation of proteoforms, cells of origin expressing specific proteins, and several bioactive PTMs and their subsequent analyses by liquid chromatography and tandem mass spectrometry.