Table 2.
Microvascular proliferation and necrosis define 3 groups of 1p/19q codeleted anaplastic oligodendrogliomas associated with distinct molecular alterations
| Group 1 No MVP no necrosis | Group 2 MVP no necrosis | Group 3 MVP and necrosis | Group 1 vs group 2 + 3 | Group 3 vs group 1 + 2 | Group 3 vs group 2 | |
|---|---|---|---|---|---|---|
| n (%) | 28 (18%) | 85 (54%) | 44 (28%) | |||
| Ki67 ≥20% (%) | 6 (21%) | 42 (49%) | 31 (72%) | P = .0007 | P = .001 | NS |
| Ki67 expression (mean) | 17 | 21 | 24 | P = .002 | P = .06 | NS |
| Chr 4 loss (%) | 7 (25%) | 22 (26%) | 18 (45%) | NS | P = .01 | P = .04 |
| Chr 9p loss (%) | 2 (7%) | 28 (33%) | 11 (28%) | P = .008 | NS | NS |
| Chr 9q loss | 0 | 19 (22%) | 7 (12.5%) | P = .008 | NS | NS |
| Chr 11q gain | 6 (21%) | 5 (6%) | 13 (32.5%) | NS | P = .002 | P = .0001 |
| Number of chr arm alteration (mean) | 4 | 4.4 | 5.7 | NS | P = .01 | P = .02 |
Abbreviations: chr., chromosome; MVP, microvascular proliferation; NS, not significant.