FAS and cancer: As a result, ethnicity (χ2 = 13.44, degree of freedom  = 3, Ph = 0.004) and cancer type (χ2 = 22.26, degree of freedom  = 11, Ph = 0.022), but not source of controls (χ2 = 1.49, degree of freedom  = 1, Ph = 0.222) or genotyping method (χ2 = 1.48, degree of freedom  = 4, Ph = 0.830) contributed to substantial heterogeneity of the Fas -670A>G polymorphism.