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hTERT expression predicts RCC survival, tumor aggressiveness



Human telomerase reverse transcriptase (hTERT) protein expression is associated with clear cell renal carcinoma (ccRCC) tumor aggressiveness and disease-specific survival (DSS), according to investigators.

Associations between hTERT expression and clinicopathologic features and outcomes were less robust or nonexistent in papillary and chromophobe subtypes, reported Leili Saeednejad Zanjani, MD, of the Oncopathology Research Center at Iran University of Medical Sciences in Tehran, and colleagues.

“Evidence shows that telomerase is expressed in 85% of malignancies, and the level of its activity is higher in advanced and metastatic tumors,” the authors wrote in Pathology.

“A number of clinical studies have been performed to evaluate the association between telomerase activity and clinicopathological parameters in renal cancer showing that telomerase activity level correlates with progression of RCC,” Dr. Zanjani and associates wrote. As none of these specifically evaluated hTERT protein expression, the investigators conducted a study to learn more.

The investigators analyzed hTERT expression level in 176 cases of RCC, requiring that each tumor had three core biopsies because of concerns of heterogeneity. The population consisted of 113 clear cell, 12 type I papillary, 20 type II papillary, and 31 chromophobe subtypes. Patient and clinicopathologic features were compared with survival and hTERT expression. Median follow-up time was 42 months.

Correlations between hTERT expression and disease characteristics were pronounced in cases of ccRCC, compared with other subtypes. In ccRCC, hTERT expression was significantly associated with tumor stage, nucleolar grade, tumor size, microvascular invasion, lymph node invasion, renal pelvis involvement, renal sinus fat involvement, Gerota fascia invasion, and distant metastasis. Survival analysis showed that DSS of ccRCC patients with high hTERT expression was 58 months, compared with 68 months for those with low hTERT expression (P =.012). Other parameters associated with survival were nucleolar grade, tumor stage, and tumor size.

For type I and II papillary subtypes, associations were found between hTERT expression and tumor stage and distant metastasis. In contrast, chromophobe RCC revealed no such relationships. No associations were found between hTERT expression and survival in any of these three latter subtypes, for slightly different reasons; no patients with type I disease died of renal cancer, disallowing creation of a Kaplan-Meier survival curve, whereas type II and chromophobe survival curves revealed insignificant relationships with hTERT expression. Along the same lines, no clinicopathologic characteristics of these subtypes were tied with survival.

“From these findings we are able to conclude that hTERT protein expression may be a novel prognostic indicator of worse outcome in tumor biopsies of patients with ccRCC, if follow up time is more prolonged,” the authors wrote. They noted that “telomerase is an attractive and ideal target for therapy due to overexpression in the majority of malignancies and low or nonexpression in most somatic cells.”

The study was funded by the Iran National Science Foundation. The authors declared no conflicts of interest.

SOURCE: Zanjani LS et al. Pathology. 2018 Nov 19. doi: 10.1016/j.pathol.2018.08.019.

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