CYP1B1 and breast carcinoma: The null polymorphism of GSTT1 was also combined with the polymorphism Val432Leu of CYP1B1. As represented in Table 4, the combination of the null genotype of GSTT1 with the altered allele of CYP1B1 were identified in 39 patients; of those, 35 were 50 years old or more at the diagnosis of breast cancer (OR 4.167; 95% CI 1.159–14.979; p-value = 0.022).