Usefulness of Liquid Biopsy for Intraocular Malignancies

Abstract

Retinoblastoma (RB) is the most common primary intraocular malignancy in children, whereas Uveal melanoma (UM) is the most common intraocular malignancy in adults [1,2]. Tissue biopsy is the standard gold technique for diagnosing the malignant neoplasm but an incisional tissue biopsy or fine needle aspiration biopsy (FNAB) is contraindicated for the intraocular malignancy [3]. Clinical diagnosis and imaging study are the only way to diagnose the intraocular malignancy due to the risk and fear of extraocular spread [4]. Recently, liquid biopsy has gained in popularity in the ophthalmic field. Liquid biopsy allows retinoblastoma diagnosis and a better understanding of the metastatic spread of uveal melanoma. Recently, the USA Food and Drug Administration (FDA) approved the make use of liquid biopsy (LB) as an appropriate diagnosis, prognosis, and also for monitoring tool in non-small cell lung carcinoma to keep away from invasive tissue biopsy in designated cases [5-7]. Liquid biopsy (LB) utilizes biofluid to evaluate for tumor-derived cells or cell-free DNA. LB is a relatively non-invasive technique rather than a tissue biopsy. In LB, material collected from multiple body fluids such as aqueous humor (AH), blood, cerebrospinal fluid, urine, and saliva for molecular diagnosis [8] and detecting of cancer biomarkers such as circulating tumor cells (CTC), tumor derived cell free DNA (ct-DNA), circulating tumor RNA (ct-RNA), microRNA (miRNA), tumorrelated exosomes (TREs), and extracellular vescicles (EVs) [7]. Aqueous humor samples for RB (Ocular LB) and Venous blood samples for UM (systemic LB) are utilizing for analyzing the molecular characteristics [8]. In others ophthalmic malignancies like conjunctival melanoma or squamous cell carcinoma, the role of LB is still not studied because tissue biopsy is routinely done for confirming the diagnosis and also for mutational status [9-11].