Analysis of CYP2B6*9 polymorphism showed that the patients displayed greater percentages of (GT) and (TT) genotypes than controls (p < 0.001 for both), carrying a 4- and 13-fold risk of developing B-CLL [(OR = 4.2, 95% CI 1.9–9.3) and (OR = 12.8, 95% CI 3.5–45.6), respectively]. The gene discussed is CYP2B6; the disease is B-cell chronic lymphocytic leukemia.