The invention relates to a compound for use for inducing apoptosis in a cancerous cell, wherein said compound is selected from the group consisting of ApoO, a variant or a fragment thereof, their mixtures, and a vector encoding for said ApoO, variant or fragment thereof. The invention further relates to a compound for use for treating a pathophysiological situation, wherein said compound is an inhibitor of the ApoO activity or of the ApoO gene expression.