Exploring tear biomarkers with shotgun proteomics for retinoblastoma diagnosis: a pilot study.

The most common ocular neoplasia among children is retinoblastoma. Currently, the diagnosis of this disease is essentially clinical, taking a biopsy is contraindicated owing to the high risk of causing metastasis. Therefore, it is imperative the development of a method to diagnose this disease through a non-invasive fashion. We choose tears as they fulfill the former precept. Through proteomic analysis we observed 52 up regulated and 48 down regulated proteins among retinoblastoma cases as compared to healthy children. Among these proteins, we identified several previously associated with retinoblastoma such as apolipoprotein A-1 (APOA1). We confirmed up regulation of APOA1 and S100 binding calcium A9 (S100A9) which revealed faithful concordance to the predicted values from mass spectrometry.