Correlation of telomere length to malignancy potential in non-melanoma skin cancers

Telomeres are associated with cell fate and aging through their role in the cellular response to stress and growth stimulation resulting from previous cell divisions and DNA damage. Telomere shortening has been observed in most human cancers, and is known to be a feature of malignancy. The aim of this study is to clarify whether telomere length is related to the malignant potential of non-melanoma skin cancers. Telomere length was analyzed using tissue quantitative fluorescence in situ hybridization in 36 non-melanoma skin cancers including basal cell carcinoma (BCC), squamous cell carcinoma (SCC), Bowen's disease (BD) and actinic keratosis (AK), and also in 26 samples of normal-appearing epidermal tissue surrounding or located close to each tumor. The fluorescence intensities of telomeres and centromeres within nuclei were determined, and the telomere-centromere ratio (TCR) was then calculated in each sample. The resulting histograms suggested that the TCR values for each type of tumor cell were distributed in a lower range than those for epidermal cells located close to the corresponding tumor type, and that the TCR values for SCC and BCC cells were distributed in a lower range than those for BD and AK cells. These results were completely consistent with the potential for metastasis and invasion of each tumor type, suggesting that telomere length in non-melanoma skin cancer cells is intrinsically linked to their biological behavior.