Comparison of surface HLA class I levels in squamous cell carcinoma cell lines of the head and neck.

Background: Squamous cell carcinomas of the head and neck (SCCHN) are the most frequent malignancies in this region. Down-regulation of human leukocyte antigen (HLA) class I was found to be implicated in the immune escape of these tumors.

Materials And Methods: Cell surface expression levels of several HLA class I antigens were evaluated in 21 SCCHN cell lines utilizing FACS analysis.

Bacteria and pathogenesis of human salivary calculus.

The exact cause of salivary calculus formation is unknown and the aim of this study was to ascertain whether bacteria play a role. Sialoliths from nine patients with chronic obstructive sialadenitis of the submandibular gland were analysed. Bacterial gene fragments were amplified from DNA extracted from salivary calculi by means of polymerase chain reaction using a universal bacterial primer pair.

Variations of EGF-R surface expression in squamous cell carcinomas of the head and neck region.

Background: It has been previously found that the epidermal growth factor receptor (EGF-R) is highly expressed in squamous cell carcinomas of the head and neck region (SCCHN) and that this expression correlates with malignant transformation and tumor development.

Materials And Methods: We examined 9 SCCHN cell lines and a control keratinocyte cell line for EGF-R expression, utilizing fluorescence-activated cell sorting (FACS) and Western blot analysis. Immuno-cytochemistry was performed to evaluate the receptor's cellular distribution.