CD44st differentially express in sensitive and MDR cancer cells. A) The expression of CD44st in various human cancer cell lines. Total RNA from sensitive and drug-resistant cells was analyzed using CD44st semi-quantitative RT-PCR. The ß-actin gene was amplified using semi-quantitative RT-PCR and used as a control. RT-PCR products were run on a 1% agarose gel to show the expression levels of the CD44st gene and ß-actin gene. The CD44st gene in these cells was also tested by DNA sequencing. B) Cell lysates from sensitive and drug-resistant cells were immunoblotted with an anti-CD44 antibody.