Comparison of frequencies of polymorphic alleles at codons 12 and 449 among US and German glioblastoma cases and race matched controls
| Series | Polymorphic allele | Wild type allele | Chi-squared | p value |
| (A) P12A | ||||
| US controls | 12 | 148 | — | — |
| Cases - USA 1 | 9 | 45 | 3.83 | p∼0.05 |
| Cases - USA 2 | 6 | 44 | 0.98 | p>0.05 |
| Cases - US 1+2 | 15 | 89 | 3.3 | p=0.07 |
| Cases - German | 9 | 79 | 0.11 | p>0.05 |
| German controls | 14 | 106 | — | — |
| (B) H449H | ||||
| US controls | 10 | 150 | — | — |
| Cases - USA 1 | 13 | 41 | 13.38 | p<0.001 |
| Cases - USA 2 | 8 | 42 | 4.62 | p=0.03 |
| Cases - US 1+2 | 21 | 83 | 11.82 | p<0.001 |
| Cases - German | 12 | 76 | 1.03 | p>0.05 |
| German controls | 11 | 109 | — | — |