hTR RNA as a Marker of Cellular Proliferation in Oral Lichen Planus

Oral lichen planus (OLP) is a common chronic inflammatory oral disorder. A number of studies have shown that OLP has a malignant potential: the rate of malignant transformation in OLP has been reported to be between 0.4 and 5.6% over ten years (Abbate et al., 2006). The WHO considers OLP to be a premalignant condition (Holmstrup, 1992). Human telomeres are regions of tandem (TTAGGG)n repeats at chromosomal ends that protect chromosomes from degradation, fusion and recombination (Moyzis et al., 1988). Telomerase maintains telomere length during cell division (Vaziri and Benchimol, 1998). Increased telomerase activity is thought to be a key event in the immortalisation of cells and has been detected in many transformed cell lines, precancerous lesions and carcinomas (Kim et al., 1994). There are three major subunits comprising the human telomerase complex. The RNA component of human telomerase (hTR) (Feng et al., 1995), telomerase associated protein (TP1) (7) and the catalytic subunit, human telomerase reverse transcriptase (hTERT) (Harrington et al., 1997). Telomerase activity has been detected in immortalised and cancer cell lines, germ line cells and most human malignancies including head and neck squamous cell carcinomas (Kim et al., 1994;