MTT assays revealed a clear dose-dependent effect of DS-7423 on cell proliferation, with all nine OCCA cell lines displaying sensitivity to DS-7423 (IC50 at 75 nM or lower), regardless of mutations on PIK3CA. The sensitivity to DS-7423 was significantly higher in OCCA than in OSA cell lines. Here, PIK3CA is linked to obstructive sleep apnea syndrome.