New aspects of brain tumor research

[The DNA methylation profiling in the study and treatment of patients with meningiomas of the craniovertebral junction]

The paper presents the experience of using DNA methylation status in patients with meningiomas of the craniovertebral junction area in a neurosurgical clinic. A clinical case of combined treatment of a patient with meningioma of the craniovertebral junction and the choice of tactics based on the result of DNA methylation analysis of meningioma are described.

Long-term outcome of 89 low-grade brain-stem gliomas after interstitial radiation therapy

Between 1974 and 1985, 89 patients suffering from histologically confirmed, nonresectable low-grade astrocytomas located in the brain stem were entered into a retrospective study. Iodine-125 (125I) was implanted in 29 patients and iridium-192 (192Ir) in 26 patients. Computerized tomography revealed that 78% of the tumors in these patients were located chiefly in the mesencephalic region, 70% were circumscribed, and 78% were contrast-enhanced. Thirty-four patients underwent biopsy without prior aggressive tumor-specific therapy such as chemotherapy or external beam irradiation. Among these, 70% of the tumors were located predominantly in the pons, 74% were diffuse, and 59% were hypodense or isodense after contrast enhancement. Long-term follow-up investigations indicated that life expectancy after interstitial radiation therapy with 125I implanted directly by catheter either permanently or temporarily showed a more favorable trend than that after treatment with 192Ir. Interstitial radiation therapy with 125I appears to be an effective treatment for slowly proliferating, differentiated, well-delineated, nonresectable brain-stem gliomas. This technique makes it possible to achieve radiosurgical tumor control and, when carefully applied, represents the least traumatic treatment. Reduction of the tumor mass brings about improvement of the clinical symptoms. Further investigations on the biological behavior of brain-stem gliomas and prospective randomized long-term follow-up studies are necessary to evaluate the different kinds of treatment available for these patients.

Oligodendrogliomas arising in the scar of a brain contusion. Report of two surgically verified cases

Several years after sustaining head injuries, two patients developed oligodendrogliomas in the scar of brain contusions. Both cases seem to fulfill the criteria currently established for accepting the traumatic origin of a brain tumor. The literature concerning the relationship between head injury and intracranial tumor is reviewed.

Techniques and results of neuroradiologic investigations of experimentally induced brain tumors in rats

In two comparable groups of 12 adult rats at a time, the normal anatomy of the cerebral arteries and the pathologic vascular pattern of experimentally induced brain tumors was investigated angiographically. These tumors were malignant mixed gliomas which were inoculated by percutaneous puncture through the vault with a suspension of 10,000 tumor cells. The neuroradiologic examinations consisted of selective angiographies of the internal carotid artery in vivo, postmortem radiographies of cerebrovascular casts of isolated brains as well as of microangiographic and comparative histologic investigations of the tumor. The juxtaventricular localization and the extension of the tumors in the basal ganglia could be angiographically demonstrated approximately 3 to 4 weeks after the implantation of the tumor cells. Moreover, qualitative and quantitative vascular criteria of malignancy could be shown microangiographically which correlated well with the histologic findings. The effects of several therapeutic procedures such as radiotherapy, pharmacoangiography and various techniques of embolization are being studied with this experimental tumor model in order to explore the prerequisites for appropriate treatment of cerebral lesions in man.

Quantitative aspects of transplantation of experimentally induced tumors of the nervous system

Quantitative aspects of transplantation have been studied experimentally in ethylnitrosourea-induced nervous system tumors. The number of cells needed for successful transplantation, the biological behaviour-increase of malignancy-of the tumor in relation to the number of cells used during the various passages, and the relationship between number of grafted cells and induction time have been examined. A "critical" number of cells was necessary to ensure a positive result; thereafter, the induction time was directly related to the logarithm of the number of cells implanted.