As a result of multivariate analysis, a predictive model was made; this identified the NAC1 LIs (OR [95% CI] 1.18 [1.11–1.28], p < 0.001) and NAC1 IRI (0.78 [0.68–0.86], p < 0.001) as predictive factors for CIS/OSCC. The gene discussed is NACC1; the disease is in situ carcinoma.