By univariate analysis, advanced ovarian cancer [advanced versus early, HR: 2.6 (95% CI 1.3–4.8), p = 0.004], ≥1 cm postoperative residual tumor [≥1 cm versus < 1 cm, HR: 3.1 (95% CI 2.0–5.0), p < 0.001], and detectable BTLA expression in cancerous tissue [detectable versus non-detectable, HR: 2.5 (95% CI 1.2–3.5), p = 0.009] were significantly associated with negative impacts on OS. The gene discussed is BTLA; the disease is ovarian cancer.