Telomerase expression in benign and malignant skin neoplasms: comparison of three major subunits.

Telomerase is a specialized ribonucleoprotein polymerase that plays an important role in maintaining cellular immortality. The multifactorial activation of telomerase, a critical step in human carcinogenesis, is not fully understood. Many studies have shown increased telomerase activity in various skin cancers. To study the regulation of telomerase in cutaneous malignancy, we used the reverse transcription polymerase chain reaction (RT-PCR) with specific primers to analyze the mRNA expression of three major telomerase subunits: human telomerase RNA (hTR), telomerase-associated protein (TP1) and human telomerase reverse transcriptase (hTERT). Clinical skin specimens were taken from 62 Taiwanese patients with a variety of skin diseases, including five from normal skin, 27 from benign tumors, 17 from malignant tumors, six from premalignant tumors, and seven from inflammatory skin diseases. TP1 was detected in 61 of 62 specimens (98.4%) and hTR was found in 58 specimens (93.6%). hTERT was more often found in specimens from malignant and premalignant tumors (73.9%, 17/23) compared to those from benign tumors (7.4%, 2/27; p < 0.0001). None of the normal skin specimens showed hTERT expression. These results indicate that expression of hTERT, but not TP1 and hTR, is highly associated with cutaneous malignancy.