| Autor: |
Jabbar, Kausar J., Luthra, Rajalakshmi, Patel, Keyur P., Singh, Rajesh R., Goswami, Rashmi, Aldape, Ken D., Medeiros, L. Jeffrey, Routbort, Mark J. |
| Zdroj: |
The American Journal of Surgical Pathology; April 2015, Vol. 39 Issue: 4 p454-461, 8p |
| Abstrakt: |
Mutation-specific antibodies for BRAFV600E and IDH1R132H offer convenient immunohistochemical (IHC) assays to detect these mutations in tumors. Previous studies using these antibodies have shown high sensitivity and specificity, but use in routine diagnosis with qualitative assessment has not been well studied. In this retrospective study, we reviewed BRAFand IDH1mutation-specific IHC results compared with separately obtained clinical next-generation sequencing results. For 67 tumors with combined IDH1 IHC and mutation data, IHC was unequivocally reported as positive or negative in all cases. Sensitivity of IHC for IDH1R132H was 98 and specificity was 100 compared with mutation status. Four IHC-negative samples showed non-R132H IDH1mutations including R132C, R132G, and P127T. For 128 tumors with combined BRAF IHC and mutation data, IHC was positive in 33, negative in 82, and equivocal in 13 tumors. The sensitivity of IHC was 97 and specificity was 99 when including only unequivocally positive or negative results. If equivocal IHC cases were included in the analysis as negative, sensitivity fell to 81. If equivocal cases were classified as positive, specificity dropped to 91. Eight IHC-negative samples showed non-V600E BRAFmutations including V600K, N581I, V600M, and K601E. We conclude that IHC for BRAFV600E and IDH1R132H is relatively sensitive and specific, but there is a discordance rate that is not trivial. In addition, a significant proportion of patients harbor BRAFnon-V600E or IDH1non-R132H mutations not detectable by IHC, potentially limiting utility of IHC screening for BRAFand IDH1mutations. |
| Databáze: |
Supplemental Index |
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