In A549 and H1299 lung cancer cells, EMP2 downregulation by SPC can specifically promote caveolin-1 expression, enhance the combination of caveolin-1 and phosphatase 2A (protein phosphatase2a, PP2A), and induce PP2A detachment from its binding protein alpha 4, and finally result in PP2A ubiquitination and degradation. Here, PTPA is linked to lung carcinoma.