Ki-67 immunoreactivity, basic fibroblastic growth factor (bFGF) expression, and microvessel density as supplementary prognostic tools in low-grade astrocytomas. An immunohistochemical study with special reference to the reliability of different Ki-67 antibodies

Immunohistochemical CD73 expression status in gastrointestinal neuroendocrine neoplasms: A retrospective study of 136 patients

The WHO 2010 classification divides gastrointestinal neuroendocrine neoplasms (GI-NENs) into neuroendocrine tumor (NET) G1, NET G2, neuroendocrine carcinoma (NEC) and mixed adenoendocrine carcinoma (MANEC) groups. A total of 136 cases of GI-NENs diagnosed at our hospitals as gastrointestinal carcinoids, endocrine cell carcinomas and NENs over the last 11 years, using the WHO 2010 classification were assessed. Among the 136 cases, 88.2% (120/136) were classified into the NET group (NET G1/G2) and 11.8% (16/136) were classified into the NEC group (NEC/MANEC). The incidences of lymphatic and venous invasions were higher in the NEC group compared with in the NET group (P<0.0001 and P=0.0021, respectively). The immunohistochemical staining of cluster of differentiation 73 (CD73) was evaluated in GI-NENs. CD73 is a potentially useful molecule in tumor immunity. In general, CD73 on the tumor cell membrane converts adenosine monophosphate to adenosine, which restrains the production of interferon-γ and cytocidal activity. Although the association between stem cells of pancreatic NENs and CD73 has been reported, few studies have reported on CD73 expression in GI-NENs. Immunohistochemical CD73 expression on the cytomembrane of neuroendocrine cells was detected in 27.2% (37/136) of the GI-NENs. The positive ratio of CD73 was significantly higher in the NEC group compared with in the NET group (P=0.0015). CD73 is also considered as a potential biomarker of anti-programmed death-1 (PD-1) therapy. The expression of programmed death-ligand 1 (PD-L1) on the cytomembrane of GI-NENs was assessed. The positive ratio of PD-L1 was higher in the NEC group compared with in the NET group (P=0.0011). Furthermore, CD73 expression status was significantly correlated with PD-L1 expression (P<0.0001). These results indicate that CD73 may be an interesting candidate for a biomarker for certain prognostic factors and therapeutics concerning PD-1 therapy.

Intratumoral hemorrhage-related differences in the expression of vascular endothelial growth factor, basic fibroblast growth factor and thioredoxin reductase 1 in human glioblastoma

The present study was designed to evaluate the expression of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF) and thioredoxin reductase 1 (TrxR1) in glioblastoma multiforme (GBM) with and without intratumoral hemorrhage. Surgically resected human GBM samples from 20 patients who underwent surgery at our institute were extracted from the histopathological specimens and divided into two groups. A total of 10 samples from each type of GBM (World Health Organization grade IV, intratumoral hemorrhage-positive or -negative) were included in each group. VEGF, bFGF and TrxR1 expression was analyzed using immunohistochemistry and the results were compared between groups. VEGF and bFGF immunoreactivity was significantly higher in GBMs containing intratumoral hemorrhage. Furthermore, VEGF, bFGF and TrxR1 immunointensity was significantly higher in GBMs containing intratumoral hemorrhage. Thus, the present study demonstrated a higher VEGF, bFGF and TrxR1 expression in GBMs contain intratumoral hemorrhage, indicatiogn a role of VEGF, bFGF and TrxR1 expression in the promotion of tumoral angiogenesis and tumoral growth by complex mechanisms that require further elucidation.

The role of neuropathology in the management of patients with diffuse low grade glioma: A systematic review and evidence-based clinical practice guideline

TARGET POPULATION

Adult patients (age ≥18 years) who have suspected low-grade diffuse glioma.

QUESTION

What are the optimal neuropathological techniques to diagnose low-grade diffuse glioma in the adult?

RECOMMENDATION

LEVEL I: Histopathological analysis of a representative surgical sample of the lesion should be used to provide the diagnosis of low-grade diffuse glioma.

LEVEL III

Both frozen section and cytopathologic/smear evaluation should be used to aid the intra-operative assessment of low-grade diffuse glioma diagnosis. A resection specimen is preferred over a biopsy specimen, to minimize the potential for sampling error issues.

TARGET POPULATION

Patients with histologically-proven WHO grade II diffuse glioma.

QUESTION

In adult patients (age ≥18 years) with histologically-proven WHO grade II diffuse glioma, is testing for IDH1 mutation (R132H and/or others) warranted? If so, is there a preferred method?

RECOMMENDATION

LEVEL II

IDH gene mutation assessment, via IDH1 R132H antibody and/or IDH1/2 mutation hotspot sequencing, is highly-specific for low-grade diffuse glioma, and is recommended as an additional test for classification and prognosis.

TARGET POPULATION

Patients with histologically-proven WHO grade II diffuse glioma.

QUESTION

In adult patients (age ≥18 years) with histologically-proven WHO grade II diffuse glioma, is testing for 1p/19q loss warranted? If so, is there a preferred method?

RECOMMENDATION

LEVEL III

1p/19q loss-of-heterozygosity testing, by FISH, array-CGH or PCR, is recommended as an additional test in oligodendroglial cases for prognosis and potential treatment planning.

TARGET POPULATION

Patients with histologically-proven WHO grade II diffuse glioma.

QUESTION

In adult patients (age ≥18 years) with histologically-proven WHO grade II diffuse glioma, is MGMT promoter methylation testing warranted? If so, is there a preferred method?

RECOMMENDATION

There is insufficient evidence to recommend methyl-guanine methyl-transferase (MGMT) promoter methylation testing as a routine for low-grade diffuse gliomas. It is recommended that patients be enrolled in properly designed clinical trials to assess the value of this and related markers for this target population.

TARGET POPULATION

Patients with histologically-proven WHO grade II diffuse glioma.

QUESTION

In adult patients (age ≥18 years) with histologically-proven WHO grade II diffuse glioma, is Ki-67/MIB1 immunohistochemistry warranted? If so, is there a preferred method to quantitate results?

RECOMMENDATION

LEVEL III

Ki67/MIB1 immunohistochemistry is recommended as an option for prognostic assessment.

Clinical Neuropathology Practice News 4-2012: levels of evidence for brain tumor biomarkers

The National Comprehensive Cancer Network (NCCN) recently published a task force report on the evaluation of the clinical utility of tumor biomarkers in oncology. In this report, common terminology and the use of levels of evidence scores to aid the evaluation of biomarker tests in oncology were proposed. Furthermore, the task force applied a level of evidence system to selected biomarkers of several cancer types. According to this system, the highest level of evidence, IA, is granted to a biomarker only if it has been evaluated in at least one adequately powered and specifically designed prospective controlled trial. For gliomas, only 1p/19q testing in oligodendroglial tumors was classified as IA by the NCCN task force. For all of the following biomarkers the present evidence level for clinical utility was regarded as lower than that of 1p/19q status: MGMT gene promoter methylation testing (glioblastoma), IDH mutation testing (diffusely growing gliomas), BRAF fusion testing (pilocytic astrocytoma) and CIMP testing (diffusely growing gliomas). The task force acknowledged that the exact application of levels of evidence needs further refinement. To our mind, the implementation of a brain tumor expert panel seems vital to evaluate the evidence levels of neurooncological biomarkers according to generally accepted criteria on a regular basis. Systematic identification of current research needs and widely accepted up-to-date recommendations for efficient biomarker application in everyday practice could be gained.

Krüppel-like factor 8 (KLF8) is expressed in gliomas of different WHO grades and is essential for tumor cell proliferation

Krüppel-like factor 8 (KLF8) has only recently been identified to be involved in tumor cell proliferation and invasion of several different tumor entities like renal cell carcinoma, hepatocellular carcinoma and breast cancer. In the present study, we show for the first time the expression of KLF8 in gliomas of different WHO grades and its functional impact on glioma cell proliferation. In order to get information about KLF8-mRNA regulation qPCR was performed and did not reveal any significant difference in samples (n = 10 each) of non-neoplastic brain (NNB), low-grade gliomas (LGG, WHO°II) and glioblastomas (GBM, WHO°IV). Immunohistochemistry of tissue samples (n = 7 LGG, 11 AA and 12 GBM) did not show any significant difference in the fraction of KLF8-immunopositive cells of all analyzed cells in LGG (87%), AA (80%) or GBM (89%). Tissue samples from cerebral breast cancer metastasis, meningiomas but also non-neoplastic brain demonstrated comparable relative cell counts as well. Moreover, there was no correlation between KLF8 expression and the expression pattern of the assumed proliferation marker Ki67, which showed high variability between different tumor grade (9% (LGG), 6% (AA) and 15% (GBM) of Ki67-immunopositive cells). Densitometric analysis of Western blotting revealed that the relative amount of KLF8-protein did also not differ between the highly aggressive and proliferative GBM (1.05) compared to LGG (0.93; p<0.05, studens t-test). As demonstrated for some other non-glial cancer entities, KLF8-knockdown by shRNA in U87-MG cells confirmed its functional relevance, leading to an almost complete loss of tumor cell proliferation. Selective blocking of KLF8 might represent a novel anti-proliferative treatment strategy for malignant gliomas. Yet, its simultaneous expression in non-proliferating tissues could hamper this approach.

The accuracy of survival time prediction for patients with glioma is improved by measuring mitotic spindle checkpoint gene expression

Identification of gene expression changes that improve prediction of survival time across all glioma grades would be clinically useful. Four Affymetrix GeneChip datasets from the literature, containing data from 771 glioma samples representing all WHO grades and eight normal brain samples, were used in an ANOVA model to screen for transcript changes that correlated with grade. Observations were confirmed and extended using qPCR assays on RNA derived from 38 additional glioma samples and eight normal samples for which survival data were available. RNA levels of eight major mitotic spindle assembly checkpoint (SAC) genes (BUB1, BUB1B, BUB3, CENPE, MAD1L1, MAD2L1, CDC20, TTK) significantly correlated with glioma grade and six also significantly correlated with survival time. In particular, the level of BUB1B expression was highly correlated with survival time (p<0.0001), and significantly outperformed all other measured parameters, including two standards; WHO grade and MIB-1 (Ki-67) labeling index. Measurement of the expression levels of a small set of SAC genes may complement histological grade and other clinical parameters for predicting survival time.

Increased L-[1-11 C] leucine uptake in the leptomeningeal angioma of sturge-weber syndrome: a PET study

BACKGROUND AND PURPOSE

We used L-[1-(11) C]leucine (LEU) positron emission tomography (PET) to measure amino acid uptake in children with Sturge-Weber syndrome (SWS), and to relate amino acid uptake measures with glucose metabolism.

METHODS

LEU and 2-deoxy-2[(18) F]fluoro-D-glucose (FDG) PET were performed in 7 children (age: 5 months-13 years) with unilateral SWS. Asymmetries of LEU uptake in the posterior brain region, underlying the angioma and in frontal cortex, were measured and correlated with glucose hypometabolism. Kinetic analysis of LEU uptake was performed in 4 patients.

RESULTS

Increased LEU standard uptake value (SUV, mean: 15.1%) was found in the angioma region in 6 patients, and smaller increases in LEU SUV (11.5%) were seen in frontal cortex in 4 of the 6 patients, despite normal glucose metabolism in frontal regions. High LEU SUV was due to both increased tracer transport (3/4 patients) and high protein synthesis rates (2/4). FDG SUV asymmetries in the angioma region were inversely related to LEU SUV asymmetries (r=-.83, P= .042).

CONCLUSIONS

Increased amino acid uptake in the angioma region and also in less affected frontal regions may provide a marker of pathological mechanisms contributing to chronic brain damage in children with SWS.

In pursuit of prognostic factors in children with pilocytic astrocytomas

OBJECTIVE

This study described a 23-year experience in the treatment of children with pilocytic astrocytomas (piloA) with the aim of identifying putative clinical, histopathological, and/or immunohistochemical features that could be related to the outcome of these patients.

METHODS

Clinical data of 31 patients under 18 years of age with piloA were obtained from 1984 to 2006.

RESULTS

The mean age at the time of surgery was 7.8 +/- 4.2 years (1 to 17 years), and the mean follow-up was 5.7 +/- 5.4 years (1 to 20 years). The most common site of tumor formation was the cerebellum (17), followed by brainstem (4), optic chiasmatic hypothalamic region (4), cerebral hemisphere (3), cervical spinal cord (2), and optic nerve (1). Gross total resection (GTR) was achieved in 23 (74.1%), mainly in those with tumors located in the cerebellum and cerebral hemispheres (P = 0.02). The global mortality rate was 6.4%. Nine patients were reoperated. Rosenthal fibers, eosinophilic granular bodies, microvascular proliferation, and lymphocytic infiltration were observed in most cases. The mean Ki-67LI was 4.4 +/- 4.5%. In all cases, Gal-3 expression in tumor cells was observed with variable staining pattern.

CONCLUSIONS

Aside from GTR, no other clinical, histopathological, or immunohistochemical features were found to be related to the prognosis. We postulate that strict follow-up is recommended if piloA is associated with high mitotic activity/Ki67-LI, or if GTR cannot be achieved at surgery. Tumor recurrence or progression of the residual lesion should be strictly observed. In some aspects, childhood piloA remains an enigmatic tumor.

The expression level of sphingosine-1-phosphate receptor type 1 is related to MIB-1 labeling index and predicts survival of glioblastoma patients

Although there are many reports on the clinical use of the MIB-1 labeling index (LI), which is a measure of proliferative activity in astrocytomas; its significance varies between studies. There are no known molecules that are directly linked to the MIB-1 LI in astrocytomas. We evaluated the clinical value of the MIB-1 LI in our human glioblastoma cases and determined the molecules that possibly influenced the MIB-1 LI. An immunohistochemical study of the MIB-1 protein was performed and MIB-1 LIs of 38 glioblastomas were determined. In the same cases, epidermal growth factor receptor (EGFR), platelet-derived growth factor receptor-alpha (PDGFRA), and sphingosine-1-phosphate receptor type 1 (S1P(1)), which are known regulators of glioma cell proliferation, were detected and quantified by quantitative real-time-PCR or western blotting. Kaplan-Meier survival curves for 38 patients with glioblastomas showed that a high MIB-1 LI correlated with poor survival (P < 0.05). Among the molecules tested, only the low expression of S1P(1) was significantly correlated with the high MIB-1 LI in glioblastomas (P < 0.05). Multivariate analysis revealed that the S1P(1) expression level was a significant prognostic factor. Our results indicate that the MIB-1 LI is an important prognostic factor in human glioblastomas. Furthermore, downregulation of S1P(1) expression increases proliferative activity, and thus enhances the malignancy of glioblastomas, resulting in a poor survival.

The clinical value of Ki-67/MIB-1 labeling index in human astrocytomas

The current WHO classification of human astrocytomas has limitations in predicting prognosis and diagnosis, and there is a need for additional factors. Several studies have investigated the clinical value of proliferative activity in these tumors, especially the Ki-67/MIB-1 labeling index (LI). The aim of this study was to review the literature on this topic to get a survey of the current experience. All studies show increasing values of Ki-67/MIB-1 LI with increasing grade of malignancy. Most of them demonstrate that MIB-1 LI differentiates well between diffuse astrocytomas WHO grade II (AII) and anaplastic astrocytomas (AA) and between AII and glioblastomas (GM), but not between AA and GM. There is, however, considerable overlap of indices between the different malignancy groups. Further, in most studies positive correlations between MIB-1 LI and survival are found, though the proposed cut-off values vary substantially between the reports. The studies reviewed report MIB-1 LI as an important prognostic factor in human astrocytomas. Due to the great spread of values between the various tumor grades, however, MIB-1 LI cannot be used as a diagnostic factor alone but should be used in combination with established criteria of histological malignancy. It may be especially useful in cases where histology reveals a low-grade astrocytoma whereas other parameters indicate a more malignant neoplasm. Thus, it is our opinion that MIB-1 LI should be a part of the routine investigation in patients with astrocytic tumors. Until larger multicenter studies based on standardized immunohistopathological procedures have been completed, each laboratory has to establish its own practice.

Prognostic significance of microvessel density determined by an anti-CD105/endoglin monoclonal antibody in astrocytic tumors: comparison with an anti-CD31 monoclonal antibody

There are conflicting reports as to whether the degree of angiogenesis as measured by microvessel density (MVD) has a prognostic value in astrocytic tumors. This may be due to the use of different antibodies against endothelial cells to highlight microvessels. It has been reported that unlike pan-endothelial antibodies, such as CD31, anti-CD105 antibodies preferentially react with endothelial cells in angiogenic tissues. To clarify the validity of anti-CD105 antibody in the evaluation of angiogenesis, we assessed MVD using an anti-CD105 monoclonal antibody (mAb) (CD105-MVD) and an anti-CD31 mAb (CD31-MVD) in a series of 50 astrocytic tumors, and correlated MVD with expression of the key angiogenic factor vascular endothelial growth factor (VEGF) and prognosis. The mean CD31-MVD and CD105-MVD was 36.7 and 24.8 for low-grade astrocytoma (LGA), 48.0 and 42.7 for anaplastic astrocytoma, 55.3 and 51.9 for glioblastoma multiforme (GBM), respectively. CD105-MVD was more closely correlated with VEGF expression than CD31-MVD. Patients with LGA and GBM showing higher CD105-MVD had a significantly shorter mean survival time (MST) than those with lower CD105-MVD tumors (P = 0.0381 and 0.0131, respectively). Whereas the MST of patients with higher CD31-MVD tumors seemed to be shorter than that of lower CD31-MVD patients within each tumor grade, the differences were not statistically significant. These findings suggest that anti-CD105 mAb may be a better marker than anti-CD31 mAb in evaluation of angiogenesis and prediction of prognosis in astrocytic tumors.