Table 1.
Studies focusing on telomerase activity and prognosis in head and neck squamous cell carcinoma cited in this review
| Authors and reference | Number of cases | Detection (assay) | Main findings |
|---|---|---|---|
| Ogawa et al., 1998 [134] | 25 patients with oral and oropharyngeal SCC (biopsies before radiotherapy, at 4,10, and 20 Gy) | TA (TRAP) | Lower levels of TA correlate with better response to radiation therapy (P = 0.025) |
| Lee et al., 2001 [130] | 46 oral SCC + 15 normal oral mucosa | TA (TRAP) | TERT correlates with TA (P < 0.001); lack of TA in normal mucosa; TERT useful marker for early detection of neoplastic cells |
| TERT mRNA (RT-PCR) | No significant correlation of TA and TERT mRNA with rate of recurrence | ||
| Patel et al. 2002 [165] | 110 HNSCC + matched adjacent mucosa 40 precancerous/benign condition | TA (TRAP) | TA in adjacent mucosa correlates with poor 2-year disease-free survival (P < 0.05) |
| Fabricius et al. 2002 [120] | 20 tumor margin from 20 patients with HNSCC + 3 tissue samples from each of 20 additional patients, one from the carcinoma centre, the tumor margin, and one distant from the tumor | TA (TRAP) | No significant associations between TA and prognosis |
| Koscielny et al. 2004 [129] | 80 HNSCC + matched adjacent mucosa | TA (TRAP) | No correlation between TA and local and regional recurrences and survival |
| Liao et al. 2004 [115] | 217 HNSCC + matched adjacent mucosa | TA (TRAP by PCR enzyme immunoassay) | High levels of TA in 63.3 % cancer tissues and only 4.1 % of adjacent mucosa. TA in cancer tissues correlates with extracapsular extension of lymph node metastases (P = 0.005) and with overall survival (P = 0.008) |
| Eissa et al. 2005 [163] | |||
| Samny et al. 2005 [162] | 35 patients with laryngeal SCC: tissue from tumor core, tumor edge, surgical resection margin, and lymph nodes (if present) | TERT mRNA (RT-PCR) | Multivariate analysis showed TERT levels in tumor edges significantly correlated with overall survival (P = 0.04) |
| Luzar et al. 2005 [166] | 40 laryngeal and 16 hypopharyngeal SCC | TERT mRNA (relative quantification by PCR based kit) | No correlation between level of TERT mRNA and overall survival |
| Freier et al. 2007 [161] | 352 HNSCC | TERT (FISH) | TERT gene amplification less common in oral SCC than in pharyngeal and laryngeal SCC (P < 0.001); however, TERT expression more frequent in oral SCC than in pharyngeal and laryngeal SCC (P = 0.047) |
| TERT (IHC) | No difference for overall and disease-free survival for HNSCC with increased TERT expression | ||
| Pannone et al. 2007 [164] | 42 oral SCC + matched adjacent mucosa | TERT mRNA (RT-PCR) TERT (IHC) | Stage I patients with higher TERT expression had a lower survival rate (P = 0.04) |
| Chen et al. 2007 [160] | 82 oral SCC + 116 oral epithelial dysplasia + 21 specimens of normal oral mucosa | TERT (IHC) | Higher nuclear TERT labeling scores significantly correlate with higher recurrence rate (P = 0.044) and shorter 5-year overall survival rate (P = 0.011) |
| Chen et al. 2008 [117] | 31 laryngeal SCC + 31 matched adjacent mucosa | TA (TRAP by PCR enzyme immunoassay) | Higher levels of TA in tumor tissue significantly correlate with shorter overall survival (P < 0.05). No correlation between TA in adjacent mucosa and overall survival |
| Fabricius et al. 2009 [126] | 40 HNSCC + 38 tumor-free surgical margin + 18 tumor-free distant from tumor | TA (TRAP) TERT (IHC) | The period without recurrence was slightly but statistically not significantly shortened in patients with higher TERT immunoreactive score (P = 0.138) |
| Qu et al. 2014 [44] | 235 laryngeal SCC | TERT promoter mutations (pyrosequencing) | TERT C250T mutation was associated with worse survival of laryngeal cancer patients (P = 0.01) |
| Boscolo-Rizzo et al. 2015 [61] | 139 HNSCC + matched adjacent mucosa | TERT mRNA (RT-PCR) | Higher TERT levels in cancer tissues significantly correlate with higher risk of regional failure (P = 0.045), distant failure (P = 0.067), and worse disease-specific survival (P = 0.037) |
FISH fluorescent in situ hybridization, HNSCC head and neck squamous cell carcinoma, IHC immunohistochemistry, PCR polymerase chain reaction, RT reverse transcriptase, SCC squamous cell carcinoma, TA telomerase activity, TERT telomerase reverse transcriptase, TRAP telomere-repeat amplification protocol