A method for determining the translation initiation inhibitory potency of a composition having an unknown level of translation initiation inhibitory activity which comprises contacting an eIF2α-WT cell with said composition for a time and at a temperature effective to inhibit proliferation of said cell, measuring the level of inhibition of proliferation of said eIF2α-WT cells induced by said sample and comparing the level of inhibition of proliferation induced by said sample with the level of inhibition of proliferation induced by a standard having a known amount of said activity, the amount of said translation initiation inhibitory activity in said sample being proportional to the level of inhibition of proliferation of said eIF2α-WT cell.