High Expression Levels of Nuclear Factor KappaB, IkappaB Kinase Alpha and Akt Kinase in Squamous Cell Carcinoma of the Oral Cavity

Background: It has been reported that the transcription factor nuclear factor kappaB (NF-kappaB) is involved in the growth, invasion, and antiapoptotic activity of cultured tumor cells.

Methods: The authors used immunohistochemistry to examine the expression of NF-kappaB and the signaling molecules leading to NF-kappaB activation in 36 untreated biopsy specimens from patients with squamous cell carcinoma (SCC) and in 15 specimens from patients with epithelial dysplasia of the oral cavity.

Results: Among the molecules examined, the p65 subunit of NF-kappaB (p65) and IkappaB kinase alpha (IKKalpha) were expressed highly in almost all SCC specimens examined, whereas the samples of normal squamous epithelia adjacent to tumors as well as epithelial dysplasia specimens were negative in for immunohistochemical staining. The invasiveness and metastasis of SCC seemed to correlate with the degree of staining degree in the molecules. Moreover, phosphorylated Akt kinase, which may be associated with antiapoptosis signaling of NF-kappaB, was detected in the same areas where IKKalpha existed in large amounts.

Conclusions: The results suggest that high expression levels of p65 and IKKalpha contribute to malignant behavior and antiapoptotic activity in SCC of the oral squamous epithelium.