PIK3CA and squamous cell carcinoma: Furthermore, patients with metastatic or recurrent squamous cell carcinomas who carried PIK3CA mutations (n = 14) achieved a median OS of 9.4 months (95% CI, 8.1–10.7), significantly longer than the median OS of those who did not carry PIK3CA mutations (n = 15; 4.2 months, 95% CI, 2.2–6.2; p = 0.019), as shown in Figure 4A.