Interaction between Rare Variants in NOTCH1 and Betel Quid Chewing in Oral Squamous Cell Carcinoma

Background: In this study, we investigated rare variants of the NOTCH1 gene located near somatic mutations as surrogate markers, as well as the relationship of these rare variants with betel quid (BQ) chewing and the occurrence of oral squamous cell carcinoma (OSCC). Materials and Methods: A total of 410 patients diagnosed with OSCC and 282 unrelated, healthy subjects without cancer were recruited from two medical centers in Taiwan. Odds ratios (OR) and 95% confidence intervals (CI) were assessed by logistic regression. The Cox proportional hazard model was used to assess the interaction between rare NOTCH1 variants and BQ chewing in OSCC. Results: The genetic variant rs139994842 in exon15 of NOTCH1 was significantly associated with an increased risk of OSCC (OR = 2.88 95% CI: 1.07-7.79), and the association between rs202133782 in exon13 of NOTCH1 with OSCC was borderline significant (p = 0.0627). Moreover, a combination of four rare variants was significantly associated with OSCC (p = 0.012). Patients who carried these NOTCH1 variants were at a higher risk of recurrence (OR = 18.95; 95% CI, 1.01-326.74; p = 0.0428). Furthermore, of the mean 24-year BQ exposure period, the OSCC incidence rate was significantly higher in OSCC patients who chewed BQ and had a NOTCH1 variant (p < 0.0001). Conclusion: This information is applicable to prevention; the surveillance of patients at risk; and for early detection to reduce morbidity and mortality from OSCC.