HES1 and ocular melanoma: To address whether soluble factors present in the OM-CM affected expression neural stem/progenitor cell markers Sox2, nestin, Notch1 and the Notch regulators Hes1 and Hes5, we looked at RNA expression of these markers in OB-ns cells expanded in OM-CM and control cultures using semi-quantitative RT-PCR [12-15].