Threo-sphingosine, (-)- is a stereoisomer of naturally occurring D-erythro-sphingosine. It is a Protein kinase C inhibitor. Threo-sphingosine, (-)- is partly active in induction of apoptosis and inhibition of MAPK activity in different kinds of solid tumor cell lines. It can be phosphorylated by cells, but the resulting L-Threo-sphingosine 1-phosphate does not bind and activate sphingosine 1-phosphate receptors, excluding their role in Threo-sphingosine, (-)-induced growth inhibition. Cell culture experiments with Diffuse large B cell lymphoma cell lines that were incubated with Threo-sphingosine, (-)- manifested significant inhibition of cell growth, while incubation of cells with similar concentrations of sphingosine 1-phosphate was ineffective. These results suggest that Threo-sphingosine, (-)- accumulation could be an alternative treatment option for Diffuse large B cell lymphoma.