Immunohistochemical detection of hTERT protein in soft tissue sarcomas: correlation with tumor grade

Human telomerase reverse transcriptase (hTERT) is a telomerase catalytic subunit that regulates telomerase activity. Telomerase is expressed in many human cancers and cell lines and is thought to contribute to their immortality. Little is known about the expression of telomerase in non-epithelial tumors. The objective of this study was to evaluate hTERT expression in a wide range of soft tissue sarcomas. A total of 154 cases of different types of soft tissue sarcoma (54 low-grade, 40 intermediate-grade, and 60 high-grade cases) were evaluated for hTERT expression using immunohistochemistry on tissue microarrays. hTERT immunoexpression was detected in 59% of cases; it was observed in 46%, 58%, and 72% of low-grade, intermediate-grade, and high-grade sarcoma cases, respectively. The intensity of staining positively correlated with the grade of the sarcomas: diffuse strong positive nuclear staining was identified in 6, 8, and 30 cases of low-grade, intermediate-grade, and high-grade sarcomas, respectively. These results suggest that telomerase expression is more often detected in highly malignant tumors than in low-grade sarcomas and thus may be a critical mechanism in tumor progression.