Immunoreactivity of glial fibrillary acidic protein (GFAP) in 38 schwannomas and 18 neurofibromas was evaluated and compared with the reactivity of vimentin, S-100 protein, and neurofilament protein. All cases were positive for vimentin and S-100 protein. GFAP was positively stained in the neoplastic cells of 15 of 38 schwannomas (38%) and in two of 18 neurofibromas (11%). The extensively stained GFAP-positive tumors tended to be deeply situated in the body. The GFAP-positive cells were usually spindle-shaped and appeared preferentially in the perivascular region of hyalinized, thick blood vessels.

Integrin alpha v beta 5 promotes FG carcinoma cell adhesion to vitronectin yet requires protein kinase C (PKC) activation for migration on this ligand. Here we report that this PKC-dependent cell motility event requires NF-kappaB-dependent transcription. Specifically, a component within nuclear extracts prepared from PKC-stimulated FG cells exhibited a significant increase in binding activity to a synthetic oligonucleotide containing a consensus kappa B sequence. These nuclear DNA-binding complexes were shown to be comprised of p65 and p50 NF-kappaB/rel family members and appeared functionally active because they promoted transcription of a reporter construct containing a kappa B site. The NF-kappa B activation event was directly linked to the alpha v beta 5 motility response because the NF-kappa B-binding oligonucleotide, when introduced into FG cells, inhibited cell migration on vitronectin but not on collagen and had no effect on cell adhesion to either ligand. These results suggest that the detected DNA-binding complexes interact with kappa B transcriptional elements to regulate gene expression required for alpha v beta 5-dependent cell motility on vitronectin.

In order to elucidate the factors contributory to the expression of invasiveness of oral squamous cell carcinoma, we conducted biochemical and morphological comparisons of well differentiated squamous carcinoma cell line OSC‐19 (oral squamous cell carcinoma) and undifferentiated carcinoma cell line KB, both cultured on 3T3 cell‐embedded collagen gel (in vitro invasion model). OSC‐19 cells invaded 3T3 cell‐embedded collagen gel, while KB cells and OSC‐19 cells on 3T3 cell‐free gel matrix were less invasive. Cultured OSC‐19 cells were characterized by lower proliferating activity, lower secretion of laminin and higher secretion of fibronectin than those of KB cells. Although the basement membrane with deposition of laminin and type IV collagen was formed, it was discontinuous at the invasion front. Gelatin zymography and western blotting showed matrix metalloproteinases (MMP), i.e., 72 kDa gelatinase (MMP‐2) and 92 kDa gelatinase (MMP‐9). Gelatinolytic activity was assayed, and was higher in OSC‐19 cells than in KB cells or OSC‐19 cells of the 3T3 cell‐free model. By immuno‐histochemical analysis, MMP‐2‐positive cells were found scattered in both cell lines without any preferential localization, and the positivity for MMP‐9 was localized in the invasion front of OSC‐19 cells. These results strongly suggest that the invasiveness of squamous cell carcinoma is well correlated with cell‐matrix adhesion by fibronectin and with focal elaboration of metalloproteinases, especially MMP‐9, which play a major role in degrading the extracellular matrix components.