Loss of H3K27 trimethylation is frequent in IDH1-R132H but not in non-canonical IDH1/2 mutated and 1p/19q codeleted oligodendroglioma: a Japanese cohort study

Oligodendrogliomas are defined by mutation in isocitrate dehydrogenase (NADP(+)) (IDH)1/2 genes and chromosome 1p/19q codeletion. World Health Organisation diagnosis endorses testing for 1p/19q codeletion to distinguish IDH mutant (Mut) oligodendrogliomas from astrocytomas because these gliomas require different treatments and they have different outcomes. Several methods have been used to identify 1p/19q status; however, these techniques are not routinely available and require substantial infrastructure investment. Two recent studies reported reduced immunostaining for trimethylation at lysine 27 on histone H3 (H3K27me3) in IDH Mut 1p/19q codeleted oligodendroglioma. However, the specificity of H3K27me3 immunostaining in this setting is controversial. Therefore, we developed an easy-to-implement immunohistochemical surrogate for IDH Mut glioma subclassification and evaluated a validated adult glioma cohort. We screened 145 adult glioma cases, consisting of 45 IDH Mut and 1p/19q codeleted oligodendrogliomas, 30 IDH Mut astrocytomas, 16 IDH wild-type (Wt) astrocytomas, and 54 IDH Wt glioblastomas (GBMs). We compared immunostaining with DNA sequencing and fluorescent in situ hybridization analysis and assessed differences in H3K27me3 staining between oligodendroglial and astrocytic lineages and between IDH1-R132H and non-canonical (non-R132H) IDH1/2 Mut oligodendroglioma. A loss of H3K27me3 was observed in 36/40 (90%) of IDH1-R132H Mut oligodendroglioma. In contrast, loss of H3K27me3 was never seen in IDH1-R132L or IDH2-mutated 1p/19q codeleted oligodendrogliomas. IDH Mut astrocytoma, IDH Wt astrocytoma and GBM showed preserved nuclear staining in 87%, 94%, and 91% of cases, respectively. A high recursive partitioning model predicted probability score (0.9835) indicated that the loss of H3K27me3 is frequent to IDH1-R132H Mut oligodendroglioma. Our results demonstrate H3K27me3 immunohistochemical evaluation to be a cost-effective and reliable method for defining 1p/19q codeletion along with IDH1-R132H and ATRX immunostaining, even in the absence of 1p/19q testing.

Use of a Variety of Biological Parameters in Distinguishing Cirrhotic from Malignant Ascites

Twenty-two different protein measurements were taken in the serum and ascitic fluid of fifty consecutive patients in an attempt to investigate which tests are the most reliable for the differential diagnosis of ascites. Serum and ascitic fluid total proteins (TPR), albumin (ALB), lactate (LAC), ferritin (FER), C3 and C4 complement factors, C-reactive protein (CRP), ceruloplasmin (CER), α2-macroglobulin (α2MG), haptoglobin (HAP), α1-antitrypsin (α1AT), α1-acid glycoprotein (α1AG), transferrin (TRF), immunoglobulins IgG, IgA, IgM and cytokines such as interleukin-1α (IL-1α), interleukin-1α (IL-1α), interleukin-2 (IL-2), interleukin-6 (IL-6), interleukin-8 (IL-8) and tumor necrosis factor-alpha (TNF-α) were measured to distinguish between malignant and cirrhotic ascites. Correlations and non-parametric Mann-Whitney tests were used for ascitic fluid:serum ratio comparisons between the two groups. Multivariate analyses were used to determine the most significant biochemical ratio predictors for the differential diagnosis and a recursive partitioning model was constructed. Highly positive correlations (r>0.50) were found between the ratios IgA, IgG, IgM, CER, α2 MG, HAP, α1AT, α1AG and TRF. There was evidence that TPR, ALB, LAC, FER, IgG, CER, α2MG, α1AT, α1AG, TRF and IL-8 ascitic fluid:serum ratios are significnatly higher in patients with malignant neoplasms than in cirrhotics. In the recursive partitioning model the most significant parameters were found to be the ratios of albumin and IL-1a. The model fitted allowed for 100% correct classification of ascites. In conclusion, we have shown that a simple and very accurate model based on two ascitic fluid: serum measurements is able to differentiate between malignant and non-malignant ascites.