<p>It is intended to establish a screening method for a cytoplasmic malate dehydrogenase inhibitor using high-performance liquid chromatography. By using this screening method, it is disclosed that a sulfonamide derivative or a sulfonic acid ester derivative showing a potent anticancer activity serves as a cytoplasmic malate dehydrogenase inhibitor. Moreover, a double-stranded RNA (more specifically speaking, shRNA) inhibiting a gene encoding cytoplasmic malate dehydrogenase is provided by RNAi and it is confirmed that proliferation of cancer cells can be thus prevented in vivo.</p>
