MAP2K7 and retinal disorder: MEK inhibitors such as trametinib and cobimetinib are approved for clinical use for different types of cancers,28 and are considered relatively safe with manageable side effects such as rashes, diarrhoea, peripheral oedema, fatigue and mild retinopathy.41,42 Therefore, it would be feasible to combine a MEK inhibitor with 5-ALA-PDT to reduce incomplete treatment responses and disease relapse in patients.