Immunohistochemical detection of human telomerase reverse transcriptase in oral cancer and pre-cancer.

Purpose: 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. Materials and 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). Conclusion: 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.

Oral Candida species in healthy and HIV-infected subjects in Chennai, South India

Objective: Candidiasis is the most common fungal infection in human immunodeficiency virus (HIV) - infected individuals. As there is sparse data on the oral <I>Candida</I> species in HIV- infected individuals in India, we characterized <I>Candida</I> species from the oral cavity in two cohorts - with and without HIV infection and with presence or absence of clinical oral candidiasis, in Chennai, South India.<br>Methods: Saliva samples were collected from 147 consecutive study participants by the oral rinse technique. <I>Candidal</I> species were isolated by culturing specimens on Sabouraud‘s dextrose agar. The pure cultures so derived were speciated using the commercially available ID32C system, and the results were interpreted using APILAB plus software.<br>Results: In the HIV seropositive group, the most commonly isolated candida species was <I>C.albicans</I> (86%) followed by <I>C.tropicalis</I> (23%), <I>C.guilliermondi</I> (6%), <I>C.krusei</I> (5%) and others (4%). In the healthy cohort without clinical candidiasis, C.tropicalis was the most commonly isolated species.<br>Conclusion: There appears to be a marked variation in oral <I>Candida</I> species found in HIV-seropositive and seronegative individuals in India. To our knowledge, this is the first attempt to identify oral Candida species in a South Indian population.