Expression of the coxsackie and adenovirus receptor (CAR) is downregulated in malignant glioma cell lines and is barely detectable in high-grade primary astrocytoma (glioblastoma multiforme). We determined the effect of forced CAR expression on the invasion and growth of the human glioma cell line U87-MG, which does not express any CAR. Although retrovirally mediated expression of full-length CAR in U87-MG cells did not affect monolayer growth in vitro, it did reduce glioma cell invasion in a 3-dimensional spheroid model. Furthermore, in xenograft experiments, intracerebral implantation of glioma cells expressing full-length CAR resulted in tumors with a significantly reduced volume compared to tumors generated by control vector-transduced U87-MG cells. In contrast, U87-MG cells expressing transmembrane CAR with a deletion of the entire cytoplasmic domain (except for the first 2 intracellular juxtamembrane cysteine amino acids) had rates of invasion and tumor growth that were similar to those of the control cells. This difference in behavior between the 2 forms of CAR was not due to improper cell surface localization of the cytoplasmically deleted CAR as determined by comparable immunostaining of unpermeabilized cells, equivalent adenoviral transduction of the cells and similar extent of fractionation into lipidrich domains. Taken together, these results suggest that the decrease or loss of CAR expression in malignant glioma may confer a selective advantage in growth and invasion to these tumors.

Cell proliferation markers are used in grading of brain tumors and in patient stratification for different treatments. Therefore, defining simple and accurate proliferation markers are of essential importance. Ki67 labeling index is widely studied, yet it is subject to interlaboratory variability. Ki67 protein is expressed on all cell cycle phases except G0 and does not precisely reflect proliferating cells. Counting mitotic figures (MFs) is used in World Health Organization grading of brain tumors (meningiomas), but the detection of MFs on conventional hematoxylin and eosin stained slides is very time consuming. Further, karyorrhexis and pyknosis in apoptotic or crushed cells may mimic mitotic morphology and falsify counting results. Histone H3 phosphorylation on serine-10 is specific to mitosis and phosphorylated histone H3 (PHH3) proliferation markers (as counts defined per area or as indices defined per cell numbers) are increasingly being used to evaluate proliferation in various tumors. Herein, we review current data on PHH3 proliferation markers in meningeal tumors. PHH3-staining highlights mitotic cells and makes easier of rapid grading by driving pathologist's attention on the most mitotically active areas. Thereby, it would function more sensitive in detecting MFs that might be otherwise overloked and more precise by reducing interobserver variability through allowing the pathologist to analyze if the stained nuclei exhibit morphologic features of mitosis.

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Female gender, contraceptives, and menopausal hormone replacement treatments containing progesterone analogues associate with higher risk of meningiomas yet with lower risk of gliomas. Progesterone receptor (PR) expression and mifepristone treatment was highly discussed for meningiomas. However, much less is known in regard to progesterone actions in gliomas despite PR expression strongly correlates with their grade. Meningiomas and gliomas may grow faster during gestation; but paradoxically, parousity reduces lifetime risk of gliomas which can be explained with dichotomous cell growth-stimulating and inhibitory actions of progesterone at low versus high levels. Progesterone levels gradually increase in gestation up to 200-fold and the incidence of highly angiogenic brain tumors decreases in the last trimester. Indeed, progesterone stimulates glial tumor cell growth at low doses (10 nM) while induces cell kill at higher doses. During gestation, some immune pathways are activated to protect the mother and the fetus against microbial pathogens. In parallel, high-dose medroxyprogesterone acetate (MPA) used in treatment of endometrial carcinoma decreases tumoral expression of PR-B and increases infiltration of cytotoxic T lymphocytes and natural killer cells. MPA also synergies with IL-2 in clinical treatment of renal cancer. In both glioma and meningioma, the dominant cytosolic PR is PR-B which increases cell growth, while PR-A limits cell growth. This seems also paradoxical at the first glance due to opposite behavior of these tumors in diverse endocrine conditions. High-dose progestins may inhibit brain tumor growth by downregulating PR-B, yet the dosage thresholds may differ between glial and meningeal tumors due to higher total PR expression in meningiomas. Supporting this proposal, certain progestins were reported to stimulate meningioma growth in anecdotal reports, but same agents at much higher doses reduced meningioma cell proliferation in pilot clinical studies. PR antagonist mifepristone reduced meningioma growth in some clinical studies, but lacked efficacy in others. In fact, mifepristone also has partial PR agonist efficacy and acts in synergy with MPA to block EC growth. Hence, a similar mechanism of receptor downregulation may also account for mifepristone. Both MPA and mifepristone also harbor myeloprotective features against chemotherapy. Ulipristal is another contraceptive PR antagonist and exerts promising anticancer activity on drug-resistant ovarian cancer and BRCA1-mutant breast cancer cells, which can be tested in animal glioblastoma models. We propose that progestins strongly deserve to be investigated in experimental models of glioblastoma alone and in combination with immunostimulating agents.

Thalassemia major continues to be a significant health problem for Mediterranean, Afro-Arabic countries, India and South Easth Asia. It was generally assumed that the β-thalassemia heterozygotes do not bear significant medical risks except a mild microcytic anemia. Nonetheless, increasing number of reports associate β-thalassemia trait with autoimmune conditions, nephritis, diabetes, arthritis, fibromyalgia and asthma. Available sparse data indicate reduced incidence of systemic lupus erythematosus (SLE) in β-thalassemia heterozygotes; yet, if two conditions coexist, the SLE manifestations occur much severer. These associations make sense when considering that the hemoglobin β-chain locus at 11p15.5 resides in close proximity to eight genes with profound roles in immune regulation: STIM1, CD151, TC21/RRAS2, SIGIRR/TOLL/IL1R8, pp52/LSP1 (lymphocyte specific protein), TRIM21, toll interacting protein (TOLLIP) and SLEN3. β-Thalassemia trait accompaniment to autoimmune disease may be the result of haplotypal associations between the close proximity genes. An alternative explanation to thalassemia heterozygosity: autoimmune disease association may be the changed concentrations of hemorphins. Hemorphins are endogenous opioid peptides derived via proteolytical cleavage of hemoglobin. They are shown to bind diverse opioid receptors and act anti-inflammatory. Their reduced expression in thalassemia heterozygosity may explain a proinflammatory stage and autoimmunity vulnerability.

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The authors describe the case of a patient with von Hippel-Lindau (VHL) disease in which a spinal hemangioblastoma contained metastatic renal cell carcinoma (RCC). The literature on tumor-to-tumor metastasis associated with VHL disease of the central nervous system (CNS) is reviewed. Midthoracic back pain developed in this 43-year-old man with a left-sided radicular component 2 years after he underwent resection of a left RCC. Radiological findings demonstrated a T6-7 intradural intramedullary lesion. A T5-8 laminectomy and gross-total resection of the spinal cord mass were performed. Light and electron microscopic examination showed features of hemangioblastoma, which contained metastatic foci of RCC. Genetic analysis demonstrated the presence of a deleting mutation in the first exon (nt. 394-406) of the VHL locus, truncating 16 amino acids (N61-77) from the first beta sheet in the VHL protein. A review of the literature revealed that RCC-to-CNS hemangioblastoma is the second most common donor-recipient tumor association among the tumor-to-tumor metastases.

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