Comparison of next-generation sequencing mutation profiling with BRAF and IDH1 mutation-specific immunohistochemistry.

Mutation-specific antibodies for BRAF V600E and IDH1 R132H 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 BRAF and IDH1 mutation-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 IDH1 R132H was 98% and specificity was 100% compared with mutation status. Four IHC-negative samples showed non-R132H IDH1 mutations 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 BRAF mutations including V600K, N581I, V600M, and K601E. We conclude that IHC for BRAF V600E and IDH1 R132H is relatively sensitive and specific, but there is a discordance rate that is not trivial. In addition, a significant proportion of patients harbor BRAF non-V600E or IDH1 non-R132H mutations not detectable by IHC, potentially limiting utility of IHC screening for BRAF and IDH1 mutations.

Molecular and clinicopathologic characterization of AML with isolated trisomy 4.

Acute myeloid leukemia (AML) with isolated trisomy 4 is rare. Associations with KIT mutations on chromosome 4q12 have been documented. The clinicopathologic features and mutational status of KIT, FLT3, NPM1, CEBPA, and RAS were assessed in 13 AML cases with isolated trisomy 4. There were 9 men and 4 women with a median age of 54 years. Median blast count was 84% (range, 24%-93%). Morphologic features varied across five 2008 World Health Organization categories. FLT3 (5/10) and NPM1 (4/10) mutations were observed at a frequency similar to normal-karyotype AML cases. KIT D816V (1/10), RAS (1/11; NRAS), and CEBPA (0/9) mutations were rare or absent. In 11 of 13 cases, complete remission was achieved. In 8 cases, relapse occurred, with median relapse-free survival of 11 months. Median overall survival was 28 months. AML with isolated trisomy 4 is rare and associated with high bone marrow blast counts and an intermediate to poor prognosis. KIT mutations are uncommon.

Clinical biology of esophageal adenocarcinoma after surgery is influenced by nuclear factor-kappaB expression.

BACKGROUND: The expression of transcriptional factor nuclear factor kappaB (NF-kappaB) in untreated esophageal cancer specimens from patients who receive preoperative chemoradiation is associated with aggressive clinical biology. We hypothesized that nuclear NF-kappaB would define clinical biology even when surgery is used as primary therapy. METHODS: Consecutive patients who did not receive any preoperative therapy were selected. Surgical cancer specimens were examined for nuclear NF-kappaB and correlated with overall survival (OS) and disease-free survival (DFS). RESULTS: One hundred twenty-three patients (stage I, 9%; stage II, 24%; stage III, 53%; stage IV, 15%) with adenocarcinoma who underwent surgery as primary therapy were analyzed. Most patients were men (90%) and the median age was 63 years. For all 123 patients, the median DFS was 21 months and the median OS was 28 months. Nuclear NF-kappaB was associated with shortened DFS (P = 0.001) in 123 patients but also in stage II (P = 0.03) and stage III (P = 0.04). Nuclear NF-kappaB was associated with shortened OS (P = 0.002) in 123 patients and in stage II (P = 0.04) and showed trend in stage III (P = 0.17). Numbers are too small for stages I and IV. In multivariate models, nuclear NF-kappaB was an independent predictor for both DFS and OS (P = 0.005 and P = 0.01). CONCLUSIONS: Our data are the first to show that NF-kappaB status significantly correlates with DFS and OS for patients with esophageal adenocarcinoma undergoing surgery as primary therapy. NF-kappaB is an independent prognosticator of outcome, even for individual stages (e.g., stages II and III). More comprehensive molecular studies could help the design of strategies to individualize therapy of esophageal adenocarcinoma.

The role of hMSH3 and hMSH6 in ovarian endometrioid carcinoma and relationship with microsatellite instability phenotype.

Frequent frameshift mutations in the DNA mismatch repair genes hMSH3, and hMSH6, have been reported in colorectal and endometrial cancers with microsatellite instability, however, it is unclear whether they are similarly altered in ovarian endometrioid carcinoma. In this study, we examined frequency of frameshift mutation and protein expression in hMSH3 and hMSH6 in ovarian endometrioid carcinoma with or without microsatellite instability. Only 1 frameshift mutation of the 16 cases with microsatellite instability-high phenotype (6%) was detected in poly(A)8 tract of the hMSH3, but not in poly(C)8 tract of hMSH6 genes. In addition, none of the 6 microsatellite instability-low or 20 microsatellite-stable tumors showed mutations in these regions in either gene. These results indicate that mutations in the mono-nucleotide tracts of hMSH3 and hMSH6 are infrequent in ovarian endometrioid adenocarcinomas, other mechanisms may play a more important role in the development of these tumors.