FAS and cancer: For the Fas -1377G>A polymorphism, the test revealed cancer type (χ2 = 22.60, degree of freedom = 8, Ph = 0.004), but not ethnicity (χ2 = 4.81, degree of freedom = 3, Ph = 0.187), source of controls (χ2 = 0.42, degree of freedom = 1, Ph = 0.518), or genotyping method (χ2 = 0.51, degree of freedom = 3, Ph = 0.917) contributed to substantial heterogeneity.