Association of Interactions between Metabolic 'Caretaker' Genes, p53, MDM2, and Tobacco Use with the Risk of Oral Cancer: A Multifactor Dimensionality Reduction Approach.

BACKGROUND: The present study investigated the association of interactions between gene polymorphisms in metabolic 'caretaker' genes (Phase I: CYP1A1, CYP2E1; Phase II: GSTM1, GSTT1), the cell cycle regulatory gene, p53, along with its negative controller, MDM-2, and the environment variable (tobacco). A nonparametric model, multifactor dimensionality reduction (MDR), was applied to analyse these interactions. MATERIALS AND METHODS: This case-control study was carried out on 242 subjects. Genomic DNA was extracted from peripheral blood lymphocytes.11 gene variants with an exposure variable (tobacco use) were analysed using MDR to identify the best locus model for gene-gene and gene-environment interactions. Statistical significance was evaluated using a 1000-fold permutation test using MDR permutation testing software (version 1.0 beta 2). The value of p<0.05 was considered statistically significant. RESULTS: The best three-locus model for gene-gene interaction included two of the p53 gene polymorphisms; rs17878362 (intron 3) and rs1042522 (exon 4) and rs6413432 in the Phase I gene, CYP2E1(DraI). The three-locus model to evaluate the gene-environment interaction included two intronic polymorphisms of the p53 gene, that is, rs17878362 (intron 3) and rs1625895 (intron 6), and rs4646903 in the Phase I gene CYP1A1*2C. The interaction graphs revealed independent main effects of the tobacco and p53 polymorphism, rs1042522 (exon 4), and a significant additive interaction effect between rs17878362 (intron 3) and rs1042522 (exon 4). CONCLUSIONS: The nonparametric approach highlighted the potential role of tobacco use and variations in the p53 gene as significant contributors to oral cancer risk. The findings of the present study will help implement preventive strategies in both tobacco use and screening using a molecular pathology approach.

Association of vitamin D receptor gene polymorphisms with breast cancer risk.

BACKGROUND: Recent literature suggests that vitamin D signaling has a protective effect against breast cancer risk. Thus, the aim of the present study was to find the association of vitamin D receptor (VDR) gene polymorphisms with breast cancer risk. MATERIALS AND METHODS: Fok1, Bsm1, Apa1, and Taq1 polymorphisms were performed by polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP) method, and Poly A polymorphism was carried out using PCR-SSCP in 140 breast cancer patients and 155 controls. RESULTS: Odds ratio was significantly higher in both homozygous variant genotypes (LL) of Poly A polymorphism of VDR (odds ratio [OR] = 5.42, 95% confidence interval [CI] = 1.19-23.31, P = 0.02) and heterozygous variant genotypes (SL) of Poly A polymorphism of VDR (OR = 3.89, 95% CI = 1.10-13.7, P = 0.03). Fok1, Bsm1, Apa1, and Taq1 polymorphisms of VDR gene were not significantly associated with breast cancer risk. CONCLUSION: Poly A polymorphism at the 3' untranslated region (UTR) of VDR gene was significantly associated with breast cancer risk in West Indian population.

Alterations in p53 Influence hTERT, VEGF and MMPs Expression in Oral Cancer Patients.

BACKGROUND: Mutant p53 is the crucial molecule in the etiopathogenesis of oral cancer. Therefore, we aimed to evaluate the impact of alterations of the p53 gene and its negative feedback regulator, MDM2, on the expression of hTERT, VEGF, and MMPs; the critical genes involved in oral cancer progression. MATERIAL AND METHODS: p53 and MDM2 genotyping were done by PCR-RFLP. p53 mutation analysis was performed using PCR-SSCP and sequencing. hTERT, VEGFA isoforms, MMP2, and MMP9 mRNA levels were analyzed by semi-quantitative Reverse Transcriptase PCR. RESULTS: Arg allele at p53 exon 4 was significantly associated with overexpression of hTERT, MMP2, and MMP9 individually. Expression of hTERT, VEGF A isoforms, MMP2 and MMP9 were significantly altered in the presence of p53 and MDM2 polymorphisms and p53 mutations in a specific combination. Mutant p53, Arg allele at p53 exon 4 locus, and G/G/or T/T genotype at MDM2revealed increased expression of hTERT, VEGF A isoforms, and MMP2/9. CONCLUSION: This study provides evidence that apart from mutant p53, naturally occurring sequence variants in p53codon 72 (Arg72Pro) (rs1042522) and MDM2 (rs2279744) significantly alter the expression of hTERT, VEGF-A isoforms, and MMP2/9 in a specific combination. The differential interaction of codon 72 variants with MDM2, hTERT, VEGF-A isoforms and MMP2/9 play a role in the aggressiveness of oral cancer. The results have important implications for oral cancer progression and should be explored for innovative treatment options.

Apoptosis stimulating protein of p53 (ASPP) 1 and ASPP2 m-RNA expression in oral cancer.

OBJECTIVE: The present study was carried out to unfold the clinical significance of apoptosis stimulating protein of p53 (ASPP) 1 and ASPP2 expression in oral cancer (OC). METHODS: Tissue specimens (malignant and their corresponding adjacent normal) from 40 pathologically confirmed OC patients treated at the Institute were included in the study. ASPP1 and ASPP2 expression were examined using semi-quantitative RT-PCR. RESULTS: The results indicated lower ASPP1 expression in OC tissues as compared to adjacent normal tissues (p = 0.085). Stratified analysis as per tumor site revealed significant down-regulation of ASPP1 in tongue cancer tissues (p = 0.005). Receiver operating characteristic curve depicted significant discriminatory efficacy in distinguishing tongue cancer tissues and adjacent normal tissues (p = 0.019). Moreover, ASPP1 expression was remarkably declined in stage II, III and IV OC tumors than stage I OC tumors (p = 0.007, 0.092 and 0.013, respectively). A similar trend was observed in buccal mucosa tumors on further analysis. ASPP2 expression was lower in moderately differentiated OC tumors as compared to well differentiated OC tumors (p = 0.061). Significantly reduced ASPP2 expression was observed in tongue cancer tumors without invasion in contrast to tumors with perineural invasion (p = 0.007). Besides, ASPP1 and ASPP2 expression was positively inter-correlated in tongue tissues (r = 0.325, p = 0.091). CONCLUSIONS: Lower ASPP1 expression in tongue cancer during malignant transformation has significance in cancer initiation. Association of reduced ASPP1 and ASPP2 expression with advanced disease stage and moderate differentiation suggests their role in OC progression. Thus, down-regulation of ASPP1 and ASPP2 may serve as potential diagnostic and prognostic indicators in OC.

Clinical significance of serum 25 hydroxyvitamin D in breast cancer: An Indian scenario.

Recent evidences suggest a protective mechanism of vitamin D signaling against breast cancer by the autocrine/paracrine manner and may modestly reduce the risk of breast cancer. Despite lots of sunshine, vitamin D deficiency is widespread in India. Moreover, there are limited studies from Indian population regarding circulatory 25(OH) D and breast cancer risk. Thus, the aim of the present study is to investigate circulatory 25(OH) D in relation to breast cancer risk and its association with various clinico-pathological parameters from Indian population. Total 297 subjects, comprising of 157 controls and 140 breast cancer patients were enrolled for the study. Circulatory 25(OH) D was analyzed by HPLC. Statistical analysis was carried out by SPSS software version 15. Further, subjects were categorized into severe, moderate, mild vitamin D deficiency and sufficiency. The prevalence of severe and moderate 25(OH) D deficiency was higher in breast cancer patients as compared to controls. Mean values of 25(OH) D were lower in breast cancer patients as compared to controls in mild, moderate and severe deficient groups (p = 0.07, p = 0.003 and p = 0.001). Moreover, 25(OH) D was significantly lower in postmenopausal breast cancer patients as compared to premenopausal breast cancer patients, particularly in severe deficient group. The levels of 25(OH) D were lower in ER and PR negative receptor status as compared to the positive receptor in severe deficient category (p = 0.06 and p = 0.09 respectively). Whereas, the mean values of 25(OH) D were lower in HER 2 negative receptor status as compared to positive receptor status in the moderate deficient category (p = 0.09). Further, severe deficient group showed significantly lower levels of 25(OH) Din TNBC as compared to luminal A subtype (p = 0.01). Thus, Results indicate that 25(OH) D deficiency might be associated with increased risk of breast cancer. Moreover, severe 25(OH) D deficiency is associated with aggressive behavior of breast cancer.

Transcriptome profiling and pathway analysis in squamous cell carcinoma of buccal mucosa.

BACKGROUND: High recurrence and poor overall survival in buccal mucosa squamous cell carcinoma (BMSCC) are not well addressed due to lack of efficient prognostic biomarkers and targeted therapies. To uncover gene candidates for the same, transcriptome profiling has been examined in BMSCC, which is not explored yet. METHODS: We compared 9 BMSCC and 2 normal oral FFPE tissues using Agilent SurePrint G3 Human gene expression v3 microarray chips. The obtained RNA signatures were interrogated in the cancer genome atlas (TCGA) dataset for alteration values and survival data. RESULTS: We found total 237 protein coding RNAs and 85 long non-coding RNAs (lncRNAs) which displayed significant differential expression with criteria of at-least 2 fold change and Benjamini Hochberg FDR < .05. In protein coding RNAs, RUNX3 and EMX2 showed utmost degree of up-regulation and down-regulation, respectively. Likewise, among lncRNAs, ARGFXP2 and lnc-SYCP3-2 displayed highest degree of up-regulation and down-regulation, respectively. Besides, an analysis of the RNA list in TCGA dataset spotted deregulation of 21 genes in both, our cohort and TCGA cohort. Among which, MRTO4 and EIF3J genes, and LINC00310, a lncRNA showed greatest expression alterations. Strikingly, at RNA expression level, up-regulation of two genes, EIF3J and SDCBP, was significantly associated with disease free survival and poor overall survival, respectively. CONCLUSION: Our data documented significant findings to enhance understanding of the disease biology. The proposed RNA candidates (RUNX3, EMX2, MRTO4, EIF3J, SDCBP and LINC00310) may serve as putative therapeutic targets and potential biomarkers for BMSCC diagnosis and prognosis.

VEGFA isoforms play a vital role in oral cancer progression.

Angiogenesis plays an important role in tumor growth and prognostication. A key angiogenesis stimulator is vascular endothelial growth factor (VEGF). The present investigation aimed to study contribution of VEGFA isoforms in oral cancer progression. Reverse transcription polymerase chain reaction and ELISA were employed to analyze tissue VEGFA isoforms and serum VEGF levels, respectively, in 109 oral cancer cases and 50 controls. VEGF183 and VEGF165 were significantly downregulated in malignant tissues as compared to adjacent normal tissues. VEGF183 and VEGF189 were significantly associated with tumor differentiation and tumor size. VEGF165 was significantly higher in recurrent early stage tumors. Serum VEGF levels were significantly higher in cases as compared to the controls and were associated with tumor differentiation. Serum VEGF levels were significantly higher in patients with recurrent advanced stage tumors. Further, patients with high levels of VEGF165 and serum VEGF levels had the worst prognosis. VEGFA isoform status and serum VEGF levels play a significant role in the progression as well as prognosis of oral cancer.

Salivary glyco-sialylation changes monitors oral carcinogenesis.

Alterations in cell membrane glycosylation play important role in oral carcinogenesis. The present study evaluated salivary sialylation changes i.e. total sialic acid (TSA), sialidase activity, linkage specific (α2-3 and α2-6) sialoproteins and sialyl transferase (ST) activity in controls, patients with oral precancerous conditions (OPC) and oral cancer. Subjects enrolled included 100 controls, 50 patients with OPC, 100 oral cancer patients, and 30 post treatment follow-ups. TSA was estimated by spectrophotometric method, sialidase activity by spectrofluorometric assay and linkage specific biotinylated lectins (α2-3: sambucus nigra agglutinin and α2-6: maackia amurensis agglutinin) were used to detect α-2,3 and α-2,6 STs and sialoproteins by ELISA and dot blot respectively. An increasing trend of salivary TSA/TP ratio, sialidase activity, α2-3 sialoproteins, α-2,3 and α-2,6 ST activities was observed from controls to patients with OPC to oral cancer patients and levels were significantly elevated in oral cancer patients as compared to the controls. Sialidase activity exhibited significant association with metastasis and infiltration. Sialidase activity, TSA/TP ratio, α-2,3 and α-2,6 ST activities were found to be higher in patients with metastasis as compared to patients without metastasis. A progressive increase in TSA/TP ratio, sialidase activity, α2-3 and α2-6 sialoproteins was observed from controls to early to advanced stage of the disease. Sialidase activity, α2-3 and α2-6 sialoproteins and ST activities were found to be decreased in complete responders; while levels were elevated in non-responders. The results documented utility of salivary sialylation endpoints, a non invasive tool in monitoring of oral carcinogenesis.

Prevalence of high-risk human papillomavirus type 16 and 18 in oral and cervical cancers in population from Gujarat, West India.

BACKGROUND: Oral and cervical cancers are major malignancies in men and women, respectively, in India. This study evaluated occurrence of human papillomavirus (HPV) 16 and 18 infections in oral and cervical cancers to estimate HPV-associated burden of these cancers in the population from Gujarat, West India. METHODS: A total of 97 malignant oral carcinoma tissues and 52 cervical carcinoma tissues were analyzed by type-specific PCR for the presence of HPV type 16 and 18 infections. RESULTS: None of the oral cancer patients revealed the presence of HPV type 16 and 18 infection. In cervical cancer, 31 (59.6%) patients were infected with HPV 16 and 18. Of these 31 HPV-positive cervical cancer patients, 28 (90.3%) were infected with HPV 16 and 3 (9.7%) were infected with HPV 18. CONCLUSION: The results suggested that HPV 16 and 18 do not play an important role in oral carcinogenesis in the population from Gujarat, West India. However, HPV 16 is highly prevalent in the cervical cancer patients, which may be considered for planning of prevention programs such as screening and vaccination in women from this region.

Evaluation of serum and salivary total sialic acid and α-l-fucosidase in patients with oral precancerous conditions and oral cancer.

OBJECTIVES: We compared serum and salivary total sialic acid/total protein (TSA/TP) ratios and α-l-fucosidase activity in patients with oral precancerous conditions (OPCs) and oral cancer to better understand the utility of saliva, in monitoring early changes occurring during oral cancer progression. STUDY DESIGN: A cross-sectional study of 100 oral cancer patients, 50 patients with OPC, and 100 controls was performed. RESULTS: Serum and salivary TSA/TP ratios and α-l-fucosidase activity were significantly higher in OPC and oral cancer patients compared to the controls. Also, levels were higher in controls and oral cancer patients with tobacco habits as compared to those without tobacco habits. CONCLUSION: Salivary TSA/TP ratio and α-l-fucosidase activity were elevated with higher magnitude than serum levels. These results suggest that a larger study may prove the use of these saliva biomarkers as a noninvasive method for detecting early changes occurring during oral carcinogenesis.

Association between p53 gene variants and oral cancer susceptibility in population from Gujarat, West India.

BACKGROUND: p53 gene variants i.e. 16 bp duplication in intron 3, Arg72Pro in exon 4 and G>A in intron 6 have been reported to modulate susceptibility to various malignancies. Therefore, the present study evaluated the role of these p53 polymorphisms in oral cancer susceptibility in a population from Gujarat, West India. METHOD: Genotype frequencies at the three p53 loci in 110 controls and 79 oral cancer cases were determined by the PCR-RFLP method. RESULTS: Heterozygous individuals at exon 4 showed protection from developing oral cancer. Homozygous wild and heterozygous individuals at intron 3 and those heterozygous at exon 4 in combination appeared to be at lowered risk. Furthermore, carriers of the 16 bp duplication allele at intron 3, proline allele at exon 4 and G allele at intron 6 were protected from oral cancer development. CONCLUSION: p53 polymorphisms, especially Arg72Pro in exon 4 could significantly modify the risk of oral cancer development in Gujarat, West Indian population.

Recent candidate molecular markers: vitamin D signaling and apoptosis specific regulator of p53 (ASPP) in breast cancer.

Regardless of advances in treatment modalities with the invention of newer therapies, breast cancer remains a major health problem with respect to its diagnosis, treatment and management. This female malignancy with its tremendous heterogeneous nature is linked to high incidence and mortality rates, especially in developing region of the world. It is the malignancy composed of distinct biological subtypes with diverse clinical, pathological, molecular and genetic features as well as different therapeutic responsiveness and outcomes. This inconsistency can be partially overcome by finding novel molecular markers with biological significance. In recent years, newer technologies help us to indentify distinct biomarkers and increase our understanding of the molecular basis of breast cancer. However, certain issues need to be resolved that limit the application of gene expression profiling to current clinical practice. Despite the complex nature of gene expression patterns of cDNAs in microarrays, there are some innovative regulatory molecules and functional pathways that allow us to predict breast cancer behavior in the clinic and provide new targets for breast cancer treatment. This review describes the landscape of different molecular markers with particular spotlight on vitamin D signaling pathway and apoptotic specific protein of p53 (ASPP) family members in breast cancer.

Glycoprotein electrophoretic patterns have potential to monitor changes associated with neoplastic transformation in oral cancer.

Alterations in glycoproteins, important cell surface constituents, have long been associated with various malignancies. The present investigation therefore explored the clinical significance of a glycoproteomics approach in patients with oral precancerous conditions (OPC) and patients with oral cancer. The study included 80 oral cancer patients, 50 patients with OPC, and 84 controls. Native polyacrylamide gel electrophoresis followed by Schiff's staining was carried out to study the alterations in glycoproteins. The results showed significant elevation (p<0.0001) of 192 kDa, 170 kDa, 116 kDa and 44 kDa glycoproteins in oral cancer patients and patients with OPC compared with controls. The odds ratio indicated a significantly higher risk for oral cancer among users and especially chewers of tobacco. The levels of all the glycoprotein bands (192 kDa, 170 kDa, 116 kDa and 44 kDa) were higher in patients with a habit of tobacco use (WHT) than in patients with no habit of tobacco (NHT) and were also higher in WHT controls than in NHT controls. Moreover, a 230 kDa glycoprotein consistently appeared only in individuals with tobacco habits and an increasing trend was observed from WHT controls to patients with OPC to WHT oral cancer patients. In conclusion, the results indicated the potential utility of glycoprotein alterations in monitoring sequential changes occurring due to tobacco consumption during neoplastic transformation.

Combined evaluation of matrix metalloproteinases and their inhibitors has better clinical utility in oral cancer.

BACKGROUND: Oral cancer is a major health hazard worldwide with increasing incidence and mortality. Cervical lymph node metastasis is a major determinant of outcome in oral cancer. The matrix metalloproteinase (MMP) system is critically involved in invasion and metastasis. Assessment of MMPs and tissue inhibitors of MMPs (TIMPs) in certain combinations might have better clinical efficacy given their potential role in the metastatic process. AIM: Plasma concentrations of MMP-2, MMP-9, TIMP-1 and TIMP-2 in 50 controls and 75 oral cancer patients (nonmetastatic, n=54; metastatic, n=21) were evaluated to assess their investigative value and role in predicting the behavior of this malignancy. METHODS: The plasma concentrations of MMP-2, MMP-9, TIMP-1 and TIMP-2 were quantified by ELISA. The best 2- and 3-marker combinations were calculated using the statistical software mROC. The diagnostic values for all the biomolecules as single markers and their combinations were estimated using the measures of diagnostic accuracy, i.e. the area under the ROC curve and the sensitivity and specificity at cutoff limits with the highest diagnostic accuracy and at the 95% limits of sensitivity and specificity, respectively. RESULTS: MMP-9, TIMP-1 and TIMP-2 were significantly elevated (p=0.000, p=0.013 and p=0.005, respectively) in oral cancer patients. MMP-9 emerged as the best single statistically significant marker in plasma for oral cancer detection. It showed an increase in diagnostic performance when tested in combination with MMP-2 and TIMP-2. The median plasma MMP-9 levels were elevated in both the metastatic and nonmetastatic groups compared with controls (p<0.004 and p<0.007, respectively). CONCLUSION: The results indicated that plasma MMP and TIMP levels in relevant combinations may facilitate clinical decisionmaking for improved management of oral cancer patients and may provide important data for selecting patients for treatment with drugs that interfere with MMP and TIMP activities.

A review on salivary genomics and proteomics biomarkers in oral cancer.

Oral cancer has emerged as an alarming public health problem with increasing incidence and mortality rates all over the world. Therefore, the implementation of newer screening and early detection approaches are of utmost importance which could reduce the morbidity and mortality associated with this disease. Sensitive and specific biomarkers for oral cancer are likely to be most effective for screening, diagnosis, staging and follow-up for this dreaded malignancy. Unlike other deep cancers, oral cancer is located in oral cavity. Hence, the direct contact between saliva and oral cancer lesion makes the measurement of tumor markers in saliva an attractive alternative to serum and tissue testing. The DNA, RNA and protein molecules derived from the living cancer cells can be conveniently obtained from saliva. Thus, salivary biomarkers, a non-invasive alternative to serum and tissue-based biomarkers may be an effective modality for early diagnosis, prognostication and monitoring post therapy status. In the current post-genomic era, various technologies provide opportunities for high-throughput approaches to genomics and proteomics; which have been used to evaluate altered expressions of gene and protein targets in saliva of oral cancer patients. The emerging field of salivary biomarkers has great potentials to prove its clinical significance to combat oral cancer. Hence, we have reviewed importance of several salivary genomics and proteomics biomarkers for oral cancer.

Matrix metalloproteinases and their inhibitors: correlation with invasion and metastasis in oral cancer.

Matrix metalloproteinases (MMPs) have been implicated in invasion and metastasis of various malignancies. The study evaluated a comprehensive profile of MMP-2 and MMP-9 and their inhibitors, tissue inhibitor of metalloproteinases-2 (TIMP-2) and tissue inhibitor of metalloproteinases-1 (TIMP-1), respectively in 50 controls and 75 patients with oral squamous cell carcinoma (OSCC). Blood samples from controls and patients as well as malignant and adjacent normal tissues from the patients were collected. The study examined pro, active and total forms of MMP-2 and MMP-9 using zymography. Enzyme-linked immunoassay (ELISA) and reverse transcription polymerase chain reaction were carried out to evaluate protein levels and mRNA expression; respectively, for the MMPs and TIMPs. Plasma pro, active and total MMP-2, MMP-9 as well as TIMP-1 and TIMP-2 levels were significantly higher in oral cancer patients as compared to the controls. mRNA expression of the MMPs and TIMPs was significantly higher in malignant tissues as compared to adjacent normal tissues. A significant positive correlation was observed between levels of proMMP-9 and active MMP-9 with differentiation, stage and infiltration. ProMMP-2 and active MMP-2 exhibited significant positive correlation with differentiation and lymph node involvement. The multivariate analysis of ELISA results revealed a significant positive correlation between MMP-2, TIMP-1 and TIMP-2 levels with lymph node involvement, stage and differentiation. The receiver operating characteristic curve (ROC) analysis showed that the levels of MMPs and TIMPs have significant discriminatory efficacy to differentiate between controls and patients. The results indicate that MMP-2, MMP-9, TIMP-1 and TIMP-2 have significant clinical usefulness for oral cancer patients. Zymographic analysis is a simple, cost effective, rapid and sensitive alternative assay.

Utility of urinary biomarkers in oral cancer.

OBJECTIVE: Oral cancer is the leading malignancy in India, with tobacco playing a major role in the etiology. The aim of the present study was to quantify nitrate+nitrite (NO2+NO3) in tobacco products as well as to study tobacco exposure related biomarkers in controls, patients with oral precancers (OPC) and oral cancer patients. MATERIALS & METHODS: Healthy individuals (n=90) were grouped into without habit of tobacco (NHT, n=30) and healthy individuals with habit of tobacco (WHT, n=60). Oral cancer patients with a tobacco habit were classified into abstinence (n=62) and non-abstinence (n=64) groups according to status at the study time. Urinary nicotine and cotinine levels were analyzed by modified high-pressure liquid chromatography (HPLC) using a UV detector. Levels of NO2+NO3 in tobacco and urine, and urinary thioether levels were estimated by spectrophotometry. RESULTS: NO2+NO3 levels in different types of tobacco product ranged between 0.13 to 3.39 mg/g. The Odds Ratio (OR) analysis indicated positive associations of both smoking and chewing habits of tobacco with high risk of development of oral cancer. Urinary nicotine, cotinine and NO2+NO3 levels were significantly elevated in WHT, patients with OPC and oral cancer patients as compared with the NHT group. This was also the case for urinary thioether levels. Levels of urinary nicotine and cotinine were also higher in the non-abstinence group with oral cancers. CONCLUSION: The results confirmed that tobacco chewing and smoking habits are prominent risk factors for development of oral cancer in the western part of India (Gujarat). Urinary nicotine, cotinine, NO2+NO3 and thioether levels can be helpful for screening programs for oral cancer.

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.

Effects of hypothermia on myocardial substrate selection.

BACKGROUND: Hypothermia lowers the metabolic rate and increases ischemic tolerance but the effects of temperature on myocardial substrate selection are not well defined. METHODS: Isolated rat hearts were perfused with physiologic concentrations of 13C labeled lactate, pyruvate, acetoacetate, mixed long-chain fatty acids, and glucose. Hearts were cooled over 5 to 10 minutes to one of four target temperatures (37 degrees, 32 degrees, 27 degrees, or 17 degrees C), then perfused for an additional 30 minutes, freeze-clamped, and extracted. 13C NMR spectra were obtained and substrate oxidation patterns were determined by isotopomer analysis. RESULTS: Although hearts in all groups were supplied with identical substrates, the percentage of acetyl-CoA oxidized within the citric acid cycle that arose from fatty acids decreased significantly from 53.8% +/- 0.8% in the 37 degrees C group to 33.1% +/- 3.3% in the 17 degrees C group. Lactate or pyruvate utilization increased from 3.3% +/- 0.5% to 25.7% +/- 3.6%, respectively (p < 0.05 by one-way ANOVA). CONCLUSIONS: These data suggest that moderate hypothermia suppresses fatty acid oxidation and deep hypothermia significantly increases utilization of lactate and pyruvate. These effects may result from relative inhibition of catabolism of complex molecules such as fatty acids, or stimulation of pyruvate dehydrogenase. These effects on substrate metabolism may play a role in myocardial protection afforded by hypothermia.

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.