title: Immunohistochemical detection of human telomerase reverse transcriptase in oral cancer and pre-cancer.
abstract: OBJECTIVE
  Telomerase is a specialized ribonucleoprotein complex that stabilizes telomeres by adding "TAG" repeats to the end of chromosomes. The catalytic subunit of telomerase is human telomerase reverse transcriptase (hTERT), whose expression is the critical determinant of telomerase activity. Telomeres and telomerases play an important role in the longevity of cell and are known to conform "immortalization" on neoplastic cells. Although there exists a lot of information on telomerase in oral cancer, very little is known about their expression in leukoplakia and oral submucous fibrosis (OSF). This study addresses this lacuna.
  
  
  METHODS
  In this preliminary study, immunohistochemistry (IHC) was used to detect the expression of hTERT protein in oral squamous cell carcinoma (OSCC) (n=30), leukoplakia (n=15), OSF (n=15) and normal oral mucosa (n=10). The cellular localization of immunostain, intensity of stain, mean nuclear labeling index (LI) and mean nuclear labeling score (LS) of hTERT protein were studied. A total number of 1000 cells were counted in each slide. All the data were analyzed using SPSS software version 10.0.2. The cellular localization of cytoplasmic/nuclear/both of hTERT stain, staining intensity and LI were compared across the groups using Pearson's χ2 test. The mean LI and LS for OSF, leukoplakia, OSCC and normal were compared using analysis of variance (ANOVA). A P-value <0.05 was considered to be statistically significant.
  
  
  RESULTS
  The mean nuclear LI increased from OSF (22.46±4.53), through normal (28.3±12.3) to OSCC (47.56±21.30) (P=0.002) and from normal (28.3±12.3), through leukoplakia (44.06±14.6), to OSCC (47.56±21.30) (P=0.00). The mean nuclear labeling score was observed to increase from OSF (37.8±15), through normal (64.9±30.7), to OSCC samples (106.9±29.77) (P=0.00) and from normal (64.9±30.7), through leukoplakia (85.6±25.1) to OSCC samples (106.9±29.77) (P=0.00).
  
  
  CONCLUSIONS
  There was increased expression of hTERT protein in OSCC and leukoplakia samples when compared to normal oral mucosa. The cellular localization, LI and LS in OSF were significantly different from OSCC and leukoplakia.
authors: Department of Oral and Maxillofacial Pathology, Ragas Dental College and Hospital, Chennai, Tamil Nadu, India. drjayanthip@gmail.com
authors: Jayanthi
authors: J
authors: Palani
authors: Vidya
authors: V
authors: Lakshminarayanan
authors: Ranganathan
authors: R
authors: Kannan
mesh_terms: D000328:Adult; D002294:Carcinoma, Squamous Cell / Q000201:enzymology / Q000473:pathology; D002467:Cell Nucleus / Q000201:enzymology / Q000648:ultrastructure; D004396:Coloring Agents; D003593:Cytoplasm / Q000201:enzymology / Q000648:ultrastructure; D005260:Female; D005456:Fluorescent Dyes; D006801:Humans; D007150:Immunohistochemistry; D007972:Leukoplakia, Oral / Q000201:enzymology / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009061:Mouth Mucosa / Q000201:enzymology / Q000473:pathology; D009062:Mouth Neoplasms / Q000201:enzymology* / Q000473:pathology; D009914:Oral Submucous Fibrosis / Q000201:enzymology / Q000473:pathology; D011230:Precancerous Conditions / Q000201:enzymology* / Q000473:pathology; D013194:Staining and Labeling; D019098:Telomerase / Q000032:analysis*
chemical_list: D004396:Coloring Agents; D005456:Fluorescent Dyes; C509186:TERT protein, human; D019098:Telomerase