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.

Vitamin B(12) and Folate Status in Head and Neck Cancer.

Deficiency of vitamin B(12) and folate is associated with causation of certain precancerous conditions and cancer. The present study was carried out on 56 controls, 167 patients with oral precancerous conditions (OPC) and 214 head and neck cancer patients, to evaluate the plasma vitamin B(12) and folate levels to determine their association with tobacco habits and vegetarianism and several sociodemographic factors. The subjects were interviewed using a health habit and diet questionnaire at the time of blood collection. Simultaneous estimations of plasma vitamin B(12) and folate were done by Dual Count Radioassay. It was found that the habit of tobacco consumption, lower education and low income were among the risk factors. A decrease in the plasma vitamin B(12) and folate levels with respect to tobacco habits, disease progression, and vegetarian diet was also observed. The individuals in the ower quartile for vitamin B(12) and folate were at a higher risk of developing OPC, as compared to those in higher quartiles. Similarly, the patients with OPC in lower quartiles were found to be at a higher risk of developing cancer than their counterparts. There was a significant positive correlation between vitamin B(12) and folate levels in the subjects consuming tobacco, and more so in patients with OPC (r=0.4330, p=0.000). Folate levels were significantly lower in patients with advanced as compared with early disease (ANOVA p=0.006 and Spearman's Rho = -0.211 and p=0.01). The results suggest, potential significance of plasma vitamin B(12) and folate levels in head and neck malignancies which needs to be confirmed by further studies on a large population.