[Molecular cell biology--basis for new diagnostic and therapeutic approaches in surgical oncology]. / Molekulare Zellbiologie--Basis für neue diagnostische und therapeutische Ansätze in der Chirurgischen Onkologie.

In the past two decades increasing research efforts have focused on the molecular biology of the cell. In the beginning, these research activities were purely academic without any direct clinical relation. A series of important discoveries, initiated particularly by the unravelling of the genetic code and the discovery of the molecular basis of gene expression and genetics, the subsequent identification of oncogenes and tumor suppressor genes and finally the description of major mechanisms which induce genetic instability in cells, now indicate the way to many new diagnostic and therapeutic strategies. In surgical oncology, these attempts are yielding the first clinical consequences. Basic aspects of molecular cell biology as far as they are relevant for surgical oncologists are discussed.

Detection of Epstein-Barr virus-DNA in tongue epithelium of human immunodeficiency virus-infected patients.

Oral hairy leukoplakia is a lesion on the lateral part of the tongue that contains replicating Epstein-Barr virus (EBV) and presages progression from human immunodeficiency virus (HIV) infection to AIDS. To clarify the role of EBV in the development of the lesions, we used filter in situ DNA hybridization to determine the prevalence of EBV and of human papillomavirus (HPV) in epithelial cells obtained on swabs from the tongue of HIV-infected patients who had hairy leukoplakia, HIV-infected patients who did not have hairy leukoplakia, and healthy uninfected control persons. In samples collected from the 35 uninfected control persons, EBV DNA could not be detected except at low concentrations in three people. In contrast, all but one of the samples from 11 HIV-infected patients who had hairy leukoplakia contained EBV DNA. Of greatest interest, in 19 of 32 HIV-infected patients who had no signs of hairy leukoplakia, EBV DNA was also detected on the epithelium of the tongue. DNA filter in situ hybridization for the detection of HPV serotypes 6, 11, 16, and 18 in all cases yielded negative results. Statistical analysis showed that the presence of EBV DNA was significantly correlated with the clinical status of the HIV-infected persons, as determined by Walter Reed staging classification, whereas hairy leukoplakia was not. It is concluded that detection of EBV DNA in oral epithelium may be an earlier and more powerful predictor of progression to AIDS than is hairy leukoplakia.

Widespread flat warts associated with human papillomavirus type 5: a cutaneous manifestation of human immunodeficiency virus infection.

Numerous flat and tinea versicolor-like warts developed on the face, trunk, and upper extremities of a 10-year-old boy with human immunodeficiency virus infection. Nucleic acid analysis of involved skin revealed human papillomavirus type 5, which has sometimes been associated with epidermodysplasia verruciformis. This human papillomavirus type has also been described in patients with common variable immunodeficiency and dyskeratosis congenita and in renal allograft recipients. Human immunodeficiency virus infection should be added to the list of immune-related disorders that predispose to widespread flat warts.

Two newly identified human papillomavirus types (HPV 40 and 57) isolated from mucosal lesions.

Two new papillomaviruses, HPV 40 and HPV 57, were isolated from a PIN lesion and an inverted papilloma of the maxillary sinus, respectively. HPV 40 showed a 13% homology to HPV 7 by reassociation kinetics and HPV 57 showed a 17% homology to HPV 2 and 25% homology to HPV 27. Hybridization of the DNA of these papillomaviruses to a wide variety of different tumor biopsies revealed that HPV 40 was present in a few genital condylomata acuminata as well as in bowenoid lesions. HPV 57 DNA was present in an oral wart, a genital condyloma acuminatum, and verrucae vulgares lesions from two immunosuppressed patients.

On the role of seizure activity in the hippocampal damage produced by trimethyltin.

Trimethyltin (TMT) causes a pattern of hippocampal damage in rats that is similar to that caused by convulsant chemicals or seen in the brains of some human epileptics. Therefore, we investigated the possible role that TMT-induced seizure activity might play in the hippocampal damage produced by this organotin. The morphologic effects of systemically administered TMT were compared to those of kainic acid given by the same route. Unlike kainate, TMT produced seizures in only a subset of treated animals and with a latency of days rather than minutes. Evaluation of morphology during the acute seizure period revealed that TMT-induced seizures were associated with a variable pattern of granule and pyramidal cell necrosis and acute dendritic swelling in the two associational/commissural hippocampal pathways, one from CA3 to CA1-CA3 and the other from the hilus to the proximal dendrites of dentate granule cells. The TMT-induced damage contrasted sharply with the acute pattern of kainate-induced damage that consisted of acute dendritic swellings in the distal granule cell dendrites, hilus and mossy fiber region. TMT-treated rats that did not exhibit seizures in the one week after injection exhibited minimal pathology during this period. These results suggest that at least part of the damage to granule and pyramidal cells produced by TMT is mediated by the seizure activity produced by this compound. Although the resulting lesions to the CA1-CA3 pyramidal cells may appear similar in both TMT- and kainate-treated rats long after injection, evaluation of acute pathology during the active seizure phase indicates that these compounds induce seizure activity in different hippocampal pathways and cause different patterns of irreversible neuronal damage as a result.

Destruction of meningeal cells over the newborn hamster cerebellum with 6-hydroxydopamine prevents foliation and lamination in the rostral cerebellum.

Intracisternal injection of 30 micrograms 6-hydroxydopamine was used to destroy meningeal cells in the newborn hamster. After 20 or 30 days the cerebella of treated animals showed severe morphological alterations including: an absence of distinct folia anterior to the primary fissure; a disruption of lamination in the same region by the displacement of both Purkinje cells and cerebellar interneurons; a reduction in size and frequency of branching of the medullary tree with anomalous anterobasal branches and splaying; reductions in the area of the molecular layer, the total area occupied by granule cells, the length of the pial surface and the length of the Purkinje cell layer of 29, 21, 57 and 27%, respectively; disorganization of the radially organized glial scaffold by outgrowth of Bergmann glial fibers and displacement of their cell bodies, the Golgi epithelial cells, and anomalous orientation, polarity, size and branching frequency of Purkinje cell dendritic trees. These findings support our earlier hypothesis that the initial destruction of meningeal cells destabilizes the cerebellar surface (basal lamina and glia limitans superficialis) and disorganizes the glial scaffold, while the neuronal cerebellar malformations are secondary to this glial defect.

Meningeal cells influence cerebellar development over a critical period.

We have investigated the influence of meningeal cells on the development of the cerebellum by destroying these cells with 6-hydroxydopamine in hamsters of different ages. The ensuing foliation and lamination disruption in the cerebellar vermis is attributed to a disintegration of the cerebellar surface and a disorganization of the glial scaffold of the cerebellar cortex due to a loss of meningeal-glial interaction in stabilizing the extracellular matrix at the glia limitans superficialis (v. Knebel Doeberitz et al. 1986, Neuroscience 17:409-426). The severity of these cerebellar defects is correlated with the ontogenetic stage at which meningeal cells are destroyed, being greatest after treatment at postnatal day 1 and decreasing thereafter until day 5 and beyond, when no abnormalities occur, although all meningeal cells are destroyed throughout. The absence of cerebellar defects after destruction of meningeal cells at day 5 or later is associated firstly with the end of the period of branching morphogenesis of the cerebellum when all folial primordia are established, and, secondly, with the maturation of the glia limitans superficialis. These findings indicate that meningeal cells stabilize the cerebellar surface and glial scaffold over a critical period that ends, when the pattern of cerebellar foliation is established, and when the glia limitans superficialis has reached a mature state. Beyond this stage glial end-feet alone are sufficient to maintain the epithelial integrity of the cerebellum.