PIK3R1 and small cell lung carcinoma: Assessing only the 134 patients with stage III SCLC, the overall MST and 5-year OS rate were 35.1 months and 38.2%, respectively. MTOR: rs2536 (T>C) and PIK3R1: rs3756668 (A>G) remained significantly associated with survival in stage III patients (Table 3). PIK3R1: rs12755 (A>C) was a borderline prognostic factor after adjusting for clinical covariates (HR adjusted = 0.242, 95% CI: 0.058–1.010).