Abstract

Background: The programmed death ligand or PDL-1 (also known as B7-H1) has been shown to inhibit tumor immunology and facilitate immune evasion. Although these mechanisms are well known in many cancers, recent evidence has suggested this function may also be active in oral cancers. To determine appropriate models to study this phenomenon, well-characterized oral cancer cell lines were screened to evaluate the presence and expression of PDL-1 or B7-H1.

Methods: Commercially available oral squamous cell carcinomas (SCC25, SCC15, CAL27) were used for this study. RNA was isolated and subsequently screened using validated primers specific for B7-H1/PDL-1. RNA was quantified and screened for purity prior to normalization and the RT-PCR screening procedure.

Results: mRNA was successfully isolated from each cell line and verified using spectrophotometric measurements and internal PCR control standards. Subsequent screening using validated primer sets revealed expression of B7-H1 in all oral cancer cell lines, with differential expression observed using the PDL-1 validated primer set. No expression was observed in the normal, non-cancerous oral gingival cell line examined.

Conclusion: These results demonstrated that the oral cancer cell lines evaluated expression mRNA which can be successfully screened using previously validated primers. However, because differential non-equivalent results were obtained when comparing the two validated primer sets, care should be taken to determine why the difference in specificity was observed and how this may affect selection and evaluation of appropriate screening tests for future clinical samples and isolates.