Abstract

Studies have reported that the telomerase could be detected in a majority of human tumor tissues, but not in most normal tissues. In tumorigenesis, the activation of telomerase seems to be an important step for somatic cells to gain the ability of indefinite proliferation and become immortal by a way of maintaining telomere length. In clinical, telomerase activity is correlated with outcomes of patients with different types of tumor. Research data have also indicated that the inhibition or absence of telomerase activity may result in cell crisis of cancer and tumor regression. However, several reports have demonstrated a telomerase-negative status in some immortalized human cells and the absence of telomerase activity in certain kind of human tumors. Additionally, previous studies have found that the expression of the human telomerase catalytic component, hTERT, in normal human somatic cells can reconstitute telomerase activity, but does not appear to induce phenotypic changes related to malignant transformation, to explain these inconsistencies, we hypothesize that telomerase activity is not enough for tumorigenesis. Multiple mutations are required for cells to acquire malignant characteristics and telomerase should be viewed as a part of multistep tumor development process. For better outcomes of malignant tumor treatment, ongoing studies should also consider about telomerase-independent mechanism in tumorigenesis.

Key words: Telomere, telomerase, somatic cells, tumorigenesis.