Hypoxia, one of the most important driving factors in the pathogenesis of proliferative retinopathy, was described as an important inducer of CCN1 gene expression through both hypoxia-inducible factor-1α-dependent and -independent mechanisms although those effects were largely described in non-vascular cells (e.g., cancer and transformed cells)31, 32. The gene discussed is CCN1; the disease is cancer.