Clinical usefulness of telomerase activation and telomere length in head and neck cancer.

BACKGROUND: Telomere shortening at every replication cycle is postulated to limit the life span of human somatic cells. In contrast, activation of telomerase is proposed to be an essential step for cancer cell immortalization. Head and neck cancer is the most common malignancy in the Indian population compared with Western countries. However, there are very few reports on telomerase activity and telomere length in head and neck cancer. METHODS: Telomerase activation and telomere length alterations were studied in tumor and adjacent normal tissues in 110 patients with head and neck cancer and 40 patients with precancerous/benign conditions. Telomerase activity and telomere lengths were determined by Telomeric Repeat Amplification Protocol (TRAP assay) and Southern blot analysis, respectively. RESULTS: Telomerase activation was observed in 78.2% of the malignant tissues, 85% of the precancerous tissues, and 53.1% of the adjacent normal tissues. Peak terminal restriction fragment length (TRF) was observed to be significantly lower in malignant tissues compared with the adjacent normal tissues. No significant correlation could be observed between telomerase activation and clinicopathologic characteristics of the patients. Two-year disease-free survival analysis showed that patients showing telomerase activation in the adjacent normal tissues and patients showing higher telomere length in malignant tissues had poor disease-free survival. CONCLUSIONS: Our results demonstrate the significant clinical usefulness of telomerase activation and telomere length for head and neck cancer patients. These markers may be helpful in predicting the clinical course of the disease and thus in identifying the patients in need of a close follow-up and vigorous adjuvant treatment.

A Study of Various Sociodemographic Factors and Plasma Vitamin Levels in Oral and Pharyngeal Cancer in Gujarat, India.

Present study examined various socio-demographic factors, dietary patterns, habit of tobacco consumption and plasma vitamin levels in 56 healthy individuals, 146 patients with oral precancerous conditions (OPC) and 132 untreated oral and pharyngeal cancer patients. The subjects were interviewed with a detailed health, habit and diet questionnaire. Plasma b-carotene, vitamin-A and vitamin-E levels were determined spectrophotometrically. An increased incidence of OPC was observed in the age group of <30 years which was associated with tobacco chewing. Whereas, incidence of cancer was in the age group of 30-60 years where habit of tobacco smoking was more prevalent. Majorities of the subjects were from rural area, poor, unaware about association of diet with cancer. The body mass index was lower (p=0.045) in patients with OPC and cancer patients as compared to the controls. Plasma b-carotene and vitamin-E levels were lower in patients with OPC (p=0.000 and 0.031, respectively) and untreated cancer patients (p=0.000 and 0.071, respectively) than the controls. ROC curve revealed that plasma vitamin levels have ability to discriminate between controls and cancer patients. Lower plasma b-carotene and vitamin-E levels were observed in tobacco consumers as compared to non-consumers. Odds ratio revealed that controls and patients with OPC having tobacco habit and lower plasma levels of b-carotene were at a higher risk (p<0.05) of developing cancer. Regression study and Analysis of Variance revealed that plasma b-carotene levels were inversely associated (r(2)=0.14, p=0.001 and F=0.000, respectively) with increase in the stage of cancer. The data provide interesting clues of potential role of diet, tobacco habits, socio-demographic status and plasma vitamin levels in etiology of oral and pharyngeal cancer in Gujarat, where no such findings are reported.