Palani Jayanthi, Lakshminarayanan Vidya, Kannan Ranganathan
Department of Oral and Maxillofacial Pathology, Ragas Dental College and Hospital, Chennai, Tamil Nadu, India.
Indian J Dent Res. 2011 Mar-Apr;22(2):362. doi: 10.4103/0970-9290.84281.
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.
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.
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).
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.
端粒酶是一种特殊的核糖核蛋白复合体，通过在染色体末端添加“TAG”重复序列来稳定端粒。端粒酶的催化亚基是人类端粒酶逆转录酶（hTERT），其表达是端粒酶活性的关键决定因素。端粒和端粒酶在细胞寿命中起重要作用，已知它们能使肿瘤细胞“永生化”。虽然关于口腔癌中端粒酶的信息很多，但关于它们在白斑和口腔黏膜下纤维化（OSF）中的表达却知之甚少。本研究旨在填补这一空白。
在这项初步研究中，采用免疫组织化学（IHC）检测hTERT蛋白在口腔鳞状细胞癌（OSCC）（n = 30）、白斑（n = 15）、OSF（n = 15）和正常口腔黏膜（n = 10）中的表达。研究了免疫染色的细胞定位、染色强度、hTERT蛋白的平均核标记指数（LI）和平均核标记评分（LS）。每张载玻片计数1000个细胞。所有数据使用SPSS软件10.0.2版进行分析。使用Pearson卡方检验比较hTERT染色的细胞质/细胞核/两者的细胞定位、染色强度和LI在各组间的差异。使用方差分析（ANOVA）比较OSF、白斑、OSCC和正常组的平均LI和LS。P值<0.05被认为具有统计学意义。
平均核LI从OSF（22.46±4.53）、正常（28.3±12.3）到OSCC（47.56±21.30）逐渐增加（P = 0.002），从正常（28.3±12.3）、白斑（44.06±14.6）到OSCC（47.56±21.30）也逐渐增加（P = 0.00）。平均核标记评分从OSF（37.8±15）经正常（64.9±30.7）到OSCC样本（106.9±29.77）逐渐增加（P = 0.00），从正常（64.9±30.7）经白斑（85.6±25.1）到OSCC样本（106.9±29.77）同样逐渐增加（P = 0.00）。
与正常口腔黏膜相比，OSCC和白斑样本中hTERT蛋白表达增加。OSF中的细胞定位、LI和LS与OSCC和白斑有显著差异。
