Since PAK3 protein is expressed at very low levels in HeLa and CaSki cells, and migrates with PAK2, which can also be detected by the N-19 PAK3 antibody (see Materials and Methods), PAK3 protein knockdown was examined in a PAK3 high expression small cell lung carcinoma cell, DMS-79. Here, PAK2 is linked to small cell lung carcinoma.