CLEVER assay: A visual and rapid RNA extraction-free detection of SARS-CoV-2 based on CRISPR-Cas integrated RT-LAMP technology.

AIM: The current scenario of COVID-19 pandemic has presented an almost insurmountable challenge even for the most sophisticated hospitals equipped with modern biomedical technology. There is an urgency to develop simple, fast and highly accurate methods for the rapid identification and isolation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infected patients. To address the ongoing challenge, the present study offers a CLEVER assay (CRISPR-Cas integrated RT-LAMP Easy, Visual and Extraction-free RNA) which will allow RNA extraction-free method to visually diagnose COVID-19. RNA extraction is a major hurdle in preventing rapid and large-scale screening of samples particularly in low-resource regions because of the logistics and costs involved. METHOD AND RESULT: Herein, the visual SARS-CoV-2 detection method consists of RNA extraction-free method directly utilizing the patient's nasopharyngeal and oropharyngeal samples for reverse transcription loop-mediated isothermal amplification (RT-LAMP). Additionally, the assay also utilizes the integration of Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-Cas12-based system using different guide RNAs of N, E and an internal control POP7 (human RNase P) genes along with visual detection via lateral flow readout-based dip sticks with unaided eye (~100 min). Overall, the clinical sensitivity and specificity of the CLEVER assay were 89.6% and 100%, respectively. CONCLUSION: Together, our CLEVER assay offers a point-of-care tool with no equipment dependency and minimum technical expertise requirement for COVID-19 diagnosis. SIGNIFICANCE AND IMPACT OF THE STUDY: To address the challenges associated with COVID-19 diagnosis, we need a faster, direct and more versatile detection method for an efficient epidemiological management of the COVID-19 outbreak. The present study involves developing a method for detection of SARS-CoV-2 in human body without RNA isolation step that can visually be detected with unaided eye. Taken together, our assay offers to overcome one major defect of the prior art, that is, RNA extraction step, which could limit the deployment of the previous assays in a testing site having limited lab infrastructure.

Clinical relevance of long non-coding RNA in acute myeloid leukemia: A systematic review with meta-analysis.

BACKGROUND: Long noncoding RNAs (lncRNAs) may function as prognostic biomarkers in acute myeloid leukaemia (AML). However, it is still unknown exactly how significant lncRNAs are for the prognosis of AML. With a focus on their prognostic and therapeutic potential, the study aimed to provide a comprehensive review of the literature regarding the role of lncRNAs in AML. METHOD: Pub Med, The Cochrane Library, Embase, Science Direct, Web of science, Scopus, and Google scholar were searched until November, 2023. Original publications of any type exploring the prognostic and therapeutic potential of lncRNAs in AML patients were included. Heterogeneity and publication bias were examined using the I2 test and a funnel plot, respectively. To quantify the relationship between various lncRNA expression in AML patient survival, odds ratios (ORs) or hazards ratios (HRs) with 95 % confidence intervals (CIs) were pooled. Quality of studies was assessed using the Critical Appraisal Checklists for Studies created by the Joanna Briggs Institute (JBI). RESULTS: Twenty-seven studies including 5665 subjects were selected for the final analysis. In patients with AML, abnormal lncRNA expression has been associated with significant worse overall survival (pooled HR = 2.05, 95 % CI = 1.79-2.30, P <0.001), shorter disease-free survival (pooled HR = 2.17, 95 % CI = 1.13-3.22, P< 0.001), and lower complete remission rate (pooled HR = 0.27, 95 % CI = 0.11-0.43, P< 0.001). Poor prognoses have been attributed to increased expression of HOX transcript antisense intergenic RNA (HOTAIR), Promoter Of CDKN1A Antisense DNA Damage Activated RNA (PANDAR), Metastasis Associated Lung Adenocarcinoma Transcript 1 (MALAT1), RP11-222K16.2, Taurine Upregulated Gene 1 (TUG1), Small Nucleolar RNA Host Gene 5 (SNHG5), Growth Arrest Specific 5 (GAS5), and H19 and decreased expression of IGF1R Antisense Imprinted Non-Protein Coding RNA (IRAIN). CONCLUSION: The prognoses of AML patients are significantly associated with abnormally expressed lncRNAs, which may be used as prognostic indicators for predicting the patient outcomes.

Small-molecule inhibitors of kinases in breast cancer therapy: recent advances, opportunities, and challenges.

Breast cancer is the most common malignancy in women worldwide and despite significant advancements in detection, treatment, and management of cancer, it is still the leading cause of malignancy related deaths in women. Understanding the fundamental biology of breast cancer and creating fresh diagnostic and therapeutic strategies have gained renewed focus in recent studies. In the onset and spread of breast cancer, a group of enzymes known as kinases are extremely important. Small-molecule kinase inhibitors have become a promising class of medications for the treatment of breast cancer owing to their capacity to specifically target kinases involved in the growth and progression of cancer. The creation of targeted treatments that block these kinases and the signalling pathways that they activate has completely changed how breast cancer is treated. Many of these targeted treatments have been approved for the treatment of breast cancer as clinical trials have demonstrated their great efficacy. CDK4/6 inhibitors, like palbociclib, abemaciclib, and ribociclib, EGFR inhibitors such as gefitinib and erlotinib and HER2-targeting small-molecule kinases like neratinib and tucatinib are some examples that have shown potential in treating breast cancer. Yet, there are still difficulties in the development of targeted medicines for breast cancer, such as figuring out which patient subgroups may benefit from these therapies and dealing with drug resistance problems. Notwithstanding these difficulties, kinase-targeted treatments for breast cancer still have a lot of potential. The development of tailored medicines will continue to be fuelled by the identification of novel targets and biomarkers for breast cancer as a result of advancements in genomic and proteomic technology.

An Inventory of Diagnostic Tools for Detection of COVID-19.

The ongoing pandemic of coronavirus disease 2019 (COVID-19) caused by SARS-COV-2 has afflicted millions of lives globally and disrupted almost all the activities of mankind. Under such pressing circumstances when no effective therapeutics are available, a fast and accurate diagnosis of the coronavirus is the only way out to limit the transmission. Since the inception of COVID-19, the demand for diagnostic tests has increased day by day and RT-PCR is the commonly used screening test that is not only time-consuming but requires sophisticated resources. To address the increasing rate of spread of COVID-19, there is an urgent need for more diagnostic tools as the research on vaccines is still at a rudimentary level. This review summarizes an inventory of the diverse and currently available diagnostic methods based on nucleic acid and serology along with some of those working on novel principles viz. CRISPR, biosensors, and NGS. Additionally, accessible diagnostic kits that are already approved by the US and European authorities for the diagnosis of COVID-19 are also suggested that will help in selecting the most effective tests under the given scenario. Taken together, this review will pave way for further strengthening the research on the rapid and safer diagnostics of SARS-COV-2.

Diagnostic efficiency of RT-LAMP integrated CRISPR-Cas technique for COVID-19: A systematic review and meta-analysis.

To address the challenges associated with COVID-19 diagnosis, we need a faster, direct, and more versatile detection method for efficient epidemiological management of the COVID-19 pandemic. RT-qPCR (reverse transcription quantitative real-time Polymerase Chain Reaction) although the most popular diagnostic method suffers from a major drawback of equipment dependency and trained molecular biologists that limits rapid and large-scale screening, particularly in low resource regions. Reverse transcription loop-mediated isothermal amplification (RT-LAMP) is a feasible alternative for RT-qPCR; however, it also suffers from the drawback of false-positive issues. Recently, RT-LAMP has been integrated with the CRISPR-Cas technique to take care of the problems associated with RT-LAMP for COVID-19 diagnosis. In this study, a meta-analysis was conducted using three scientific databases considering the PRISMA guidelines to assess the diagnostic efficiency of RT-LAMP integrated CRISPR-Cas technology. Out of a total of 1286 studies on COVID-19, we identified 15 articles that met our eligibility criteria of using simultaneous RT-LAMP and CRISPR-Cas technique. Our meta-analysis of the included studies revealed that most of the studies were conducted in the USA with the N gene as the most common target and fluorescence-based detection method. The meta-analysis results of all included studies have further revealed a pooled sensitivity value of higher than 85% and a pooled specificity value of 80% with the confidence interval of 95%, respectively, as revealed from the forest plot and SROC curve. The accuracy rate of included studies was also calculated which varied from 77.4% to 100%. Furthermore, the precision of included studies varied from 75% to 100%. Lastly, a quality assessment of bias and applicability was performed based on QUADAS-2. Taken together, combined RT-LAMP and CRISPR-Cas technique could be a potential alternative to RT-qPCR particularly in low resource regions having a high demand for rapid testing.

Recent trends of natural based therapeutics for mitochondria targeting in Alzheimer's disease.

Alzheimer's disease (AD) is the most ubiquitous neurodegenerative disorder with impaired cognitive functionality. Till date, the specific pathophysiology related to AD is still elusive. Recent reports suggest mitochondrial dysfunctionality like oxidative stress, Ca2+ disbalance, apoptosis, decrease energy and its metabolism plays an important. Recent reports about mitochondrial mechanisms and dynamics in AD unravelled new insights of molecular targets. Targeting multi-pathway via natural products may attenuate and prevent the mitochondria dysfunctionality. In this review, we have focused on the pathophysiology events of mitochondrial dysfunction in AD as well as mitochondrial fusion and fission mechanisms, role of aging in multicellular organisms, and how these connect to cell cycle regulation, and transmission of energy status.

Polymorphism in glutathione S-transferases: susceptibility and treatment outcome for head and neck cancer.

The study investigates the association of polymorphism in glutathione S-transferases (GSTs) with susceptibility for head and neck squamous cell carcinoma (HNSCC) and its sites as well as treatment response in cases receiving chemotherapy (CT) and combination of CT-radiotherapy (CT-RT). The case-control study included 500 male cases and an equal number of healthy male controls. Odds ratios (ORs) and 95% confidence intervals (95% CI) were calculated for the association between genotypes and cancer risk. An increase in the risk for HNSCC and cancers of oral cavity, larynx or pharynx was observed in cases with null genotypes of GSTM1 or GSTT1. The interaction of alcohol or tobacco with variant genotypes of GSTM1 or GSTT1 also resulted in a significant increase in the risk for HNSCC. Further, HNSCC cases carrying the null genotypes of GSTM1 and GSTT1 or variant genotypes of GSTP1 showed a significant and superior treatment response. The present data thus provides evidence for the association of polymorphisms in GSTs with risk for HNSCC and its treatment response.

Polymorphism in cytochrome P4502A6 reduces the risk to head and neck cancer and modifies the treatment outcome.

The present case-control study consisting of 1300 cases of head and neck squamous cell carcinoma (HNSCC) and the equal number of controls aimed to investigate the association of functionally important polymorphisms in cytochrome P4502A6 (CYP2A6*1B, CYP2A6*4C, CYP2A6*9-rs28399433) with HNSCC and the treatment response in cases receiving a combination of chemotherapy/radiotherapy (CT/RT). A significant decrease in risk to HNSCC was observed in the cases with deletion (CYP2A6*4B and CYP2A6*4C) or reduced activity genotypes (CYP2A6*9) of CYP2A6. This risk to HNSCC was further reduced significantly in tobacco users among the cases when compared to nontobacco users among the cases. The risk was also reduced to a slightly greater extent in alcohol users among the cases when compared to nonalcohol users among the cases. In contrast with decreased risk to HNSCC, almost half of the cases with variant genotypes of CYP2A6 (CYP2A6*1A/*4C+*1B/*4C+*4C/*4C and *9/*9) did not respond to the treatment. Likewise, the survival rate in cases receiving the treatment, after 55 months of follow-up was significantly lower in cases with deletion (6.3%) or reduced activity (11.9%) allele than in the cases with common alleles (41%). The present study has shown that CYP2A6 polymorphism significantly reduces the risk to HNSCC. Our data further suggested that CYP2A6 polymorphism may worsen the treatment outcome in the cases receiving CT/RT.

Interaction of drug metabolizing cytochrome P450 2D6 poor metabolizers with cytochrome P450 2C9 and 2C19 genotypes modify the susceptibility to head and neck cancer and treatment response.

The present case-control study attempted to investigate the association of poor metabolizer (PM) genotypes of cytochrome P450 2D6 (CYP2D6*4 and CYP2D6*10) with squamous cell carcinoma of head and neck (HNSCC) and treatment response in patients receiving chemotherapy or combination of chemo- and radiotherapy. Cases with the PM genotypes of CYP2D6 displayed a significantly increased risk for HNSCC as compared to wild type genotypes. The risk was found to further increase in cases (up to 4.8) carrying combination of PM genotypes of CYP2D6, CYP2C9 (CYP2C9*2) or CYP2C19 (CYP2C19*2), suggesting that synergism amongst the PM genotypes of drug metabolizing CYPs leads to impairment in the detoxification of the tobacco carcinogens. A small increase in the risk in tobacco (chewers or smokers) or alcohol users in cases with CYP2D6*4 allele while no change or even a small decrease in risk in cases with CYP2D6*10 allele when compared to non-tobacco or alcohol users have suggested that CYP2D6 genotypes alone do not appear to interact significantly with environmental risk factors in modifying the susceptibility to HNSCC. Furthermore, most of the cases carrying PM genotypes of CYP2D6 did not respond to the treatment. Moreover, higher prevalence of non-responders among cases carrying combination of CYP2D6*4 or CYP2D6*4, CYP2C9*2 and CYP2C19*2 have demonstrated that interaction of PM genotypes may not only significantly modify the susceptibility to HNSCC but also the treatment response.

Association of functionally important polymorphisms in cytochrome P450s with squamous cell carcinoma of head and neck.

Head and neck squamous cell carcinoma (HNSCC), a common malignancy that possibly involves a combination of exposure to the carcinogens and inherited genetic differences in the enzymes catalyzing their metabolism. Alcohol and tobacco consumption are the primary environmental risk factors, while polymorphism in various biotransformation enzymes such as cytochrome P450s (CYPs) and glutathione S-transferases, (GSTs) has been implicated as the major genetic risk factors for the development of HNSCC. The functionally important polymorphisms in these CYPs (1AI*2A, 1A1*2C, 1B1*2, 2E1*5B, 2E1*6, 2C19*2, 2D6*4, 2D6*10) and GSTs (GSTM1-null or GSTT1-null) were found to be significantly associated with HNSCC risk. Significant differences in the distribution of certain haplotypes of CYPs have also been reported and prevalence of certain genotype combinations of CYPs and GSTS in cases has indicated the importance of gene-gene interactions in HNSCC risk. Alcohol or tobacco use (smoking and chewing) were also found to interact synergistically with variant genotypes of these CYPs and GSTS in significantly enhancing HNSCC risk. This increase in risk associated with the variant genotypes with tobacco or alcohol use have further demonstrated the importance of gene-environment interactions in determining the susceptibility to HNSCC.

Interaction of glutathione-s-transferase genotypes with environmental risk factors in determining susceptibility to head and neck cancer and treatment response and survival outcome.

The present case-control study aimed to investigate the role of interaction of glutathione-s-transferase (GST) genotypes with environmental risk factors in determining susceptibility to head and neck squamous cell carcinoma (HNSCC) involving 1,250 cases and equal number of healthy controls. An increase in the risk of HNSCC and its subsites (larynx, pharynx, and oral cavity) was observed among the cases with null genotypes of GSTM1 (odds ratio [OR] = 1.87) or GSTT1 (OR = 1.39) while reduced risk (OR = 0.81) was observed the cases with variant genotype of GSTP1. Tobacco use in the form of smoking or chewing interacted multiplicatively with GSTM1 or GSTT1 to increase the risk several folds (3-10 folds) in HNSCC and its subsites. Alcohol use also increased the risk (2-3 folds) to HNSCC and its subsites in cases with null or variant genotypes of GSTs, though this risk was of lesser magnitude when compared to the tobacco users. A synergistic effect of both, tobacco smoking and alcohol drinking, led to several folds (25-folds) increased risk to HNSCC among the cases with null genotype of GSTM1 and GSTT1 when compared to nonsmokers and nondrinkers with wild genotype of GSTM1 and GSTT1 in controls. Furthermore, cases with variant genotypes of GSTP1 (Val/Val) showed superior treatment response with improved survival rate and lower risk of death when compared to the patients with wild type genotype (Ile/Ile). The data suggest that though polymorphism in GSTs may be a modest risk factor for determining HNSCC risk, gene-environment interactions significantly modify the susceptibility to HNSCC by several folds.

Polymorphism in cytochrome P4501A1 is significantly associated with head and neck cancer risk.

A case control study was undertaken to investigate the association of polymorphisms in cytochrome P4501A1 (CYP1A1) with squamous cell carcinoma of head and neck (HNSCC) in North Indian population. The variant genotypes of CYP1A1*2A and CYP1A1*2C were found to be overrepresented in cases when compared to controls. The HNSCC risk also increased several folds in cases with combination of variant genotypes of CYP1A1*2A or CYP1A1*2C with null genotype of glutathione-S-transferase M1 (GSTM1), a phase II enzyme, particularly in cases who were tobacco users (smokers and tobacco chewers), demonstrating the role of gene-gene and gene-environment interactions in the development of HNSCC.

Polymorphism in cytochrome P450 2A6 and glutathione S-transferase P1 modifies head and neck cancer risk and treatment outcome.

A case control study was carried out to investigate the association of functionally important polymorphism in cytochrome P450 2A6 (CYP2A6) and glutathione S-transferase P1 (GSTP1) genes with head and neck squamous cell carcinoma (HNSCC) and treatment response in cases receiving a combination of chemo-radiotherapy. The study group consisted of 350 males suffering from HNSCC and an equal number of male controls. Multivariate logistic regression analysis revealed statistically significant decrease in risk to HNSCC in cases with variant genotypes (CYP2A6*1B and CYP2A6*4C) of CYP2A6 (OR: 0.78; 95% CI: 0.43-1.22; P=0.04) or GSTP1 (OR: 0.71; 95% CI: 0.51-1.00; P=0.05). The risk associated with these variant genotypes was found to be further decreased in cases carrying a combination of variant genotypes of CYP2A6 and GSTP1 (OR: 0.40; 95% CI: 0.25-0.65; P=0.00). A similar decrease in risk was observed in cases with variant genotypes of CYP2A6 (OR: 0.59; 95% CI: 0.40-0.86; P=0.00) or GSTP1 (OR: 0.62; 95% CI: 0.42-0.91; P=0.01) and who were regular tobacco users (cigarette smokers or tobacco chewers). Interestingly, only 27% of the cases carrying the variant forms of CYP2A6 (*1A/*4C+*1B/*4C+*4C/*4C) responded to the treatment for HNSCC when compared to those with wild-type genotype (69%). However with GSTP1, cases with homozygous mutant genotype (Val/Val) showed a superior treatment response (75%) when compared to cases with wild-type genotype (25%). Further, cases carrying a combination of variant genotype of CYP2A6 and wild-type genotype of GSTP1 exhibited a very poor treatment response demonstrating that polymorphisms in CYP2A6 and GSTP1 not only modified the risk to HNSCC but also played a major role in determining the chemotherapeutic response.

Polymorphism in cytochrome P450 2E1 and interaction with other genetic risk factors and susceptibility to alcoholic liver cirrhosis.

The association of polymorphism in cytochrome P450 2E1 (CYP2E1), the major microsomal ethanol metabolizing enzyme and its interaction with genes, involved in detoxification of reactive oxygen species, such as glutathione-S-transferases M1 (GSTM1) and alcohol intake, gamma-aminobutyric acid receptor gamma2 (GABRG2) was studied with the risk to alcoholic cirrhosis in a case-control study. A total of 160 alcoholic cirrhotic and 125 non-alcoholic cirrhotic cases, visiting the OPD facility of Gastroenterology Department of Sanjay Gandhi Post Graduate Institute of Medical Sciences (SGPGI), Lucknow, India and 250 non-alcoholic and 100 alcoholic controls having no evidence of liver disease were included in the study. PCR-based RFLP methodology was followed for genotyping studies. Our data revealed that the variant genotypes of CYP2E1 5B exhibited significant association with the alcoholic liver cirrhosis when compared to non-alcoholic controls (OR: 4.3; 95%CI: 1.5-12.4; p: 0.003) or non-alcoholic cirrhosis patients (OR: 5.4; 95%CI: 1.2-24.5; p: 0.01) or alcoholic controls (OR: 4.3; 95%CI: 0.95-19.62; p: 0.04). Haplotype approach revealed that haplotype T-A-T was found to be associated with more than 5-fold increase in risk for alcoholic cirrhosis. Likewise, combination of variant genotype of CYP2E1 5B with null genotype of GSTM1, a phase II detoxification enzyme, resulted in several fold increase in risk in alcoholic cirrhotic patients when compared with non-alcoholic controls or non-alcoholic cirrhotic patients. Further, the combination of variant genotype of CYP2E1 5B with GABRG2, significantly increased the risk upto 6.5-fold in alcoholic cirrhotic patients when compared with non-alcoholic controls thereby suggesting the role of gene-gene interaction in alcoholic cirrhosis.

Association of genetic polymorphisms in glutathione S-transferases and susceptibility to head and neck cancer.

Polymorphism in glutathione S-transferase (GST) genes (GSTM1, GSTT1 and GSTP1) and interaction with environmental factors such as tobacco (smoking or chewing) and alcohol on susceptibility to head and neck squamous cell carcinoma (HNSCC) was studied in a case-control study. The study group consisted of 175 patients suffering from HNSCC and 200 age matched healthy controls. Statistical analysis showed an increase in risk to HNSCC in the patients with null genotype of GSTM1 (OR: 2.02; 95% CI: 1.32-3.10; P=0.001) or GSTT1 (OR: 1.66; 95% CI: 1.02-2.69; P=0.04), though the risk was not found to be significant when adjusted for age, sex, smoking, tobacco chewing or alcohol use by multivariate logistic regression model. Our data further showed that combination of deletion genotypes of GST (GSTM1 and GSTT1) confer an even higher risk of HNSCC. Interestingly, GSTP1 wild type genotype in combination with GSTM1 null or GSTT1 null genotype increased susceptibility for HNSCC (OR: 2.49 and 2.75, respectively). Likewise a much greater risk for HNSCC was observed in the patients carrying a genotype combination of GSTM1 null, GSTT1 null and GSTP1 (Ile/Ile) (OR: 4.47; 95% CI: 1.62-12.31; P=0.002). Our data have further provided evidence that tobacco chewing and alcohol consumption are the important risk factors for HNSCC. The interaction between tobacco chewing and null genotype of GSTM1 or GSTT1 resulted in about 3.5- and 2.2-fold increase in the risk respectively in the patients when compared to those not chewing tobacco. Alcohol use resulted in more than 4-fold increase in the risk in the patients with null genotype of GSTM1 as compared to those who are non-drinkers. Alcohol consumption also increased the risk (approx. 3-fold) in the cases with null genotype of GSTT1, though the association was not found to be significant when compared to non-drinkers. Our data have provided evidence that GST polymorphism modifies the susceptibility to HNSCC and have further demonstrated importance of gene-environment interaction in modulating the risk to HNSCC.

Association of poor metabolizers of cytochrome P450 2C19 with head and neck cancer and poor treatment response.

A case-control study consisting of 300 patients and an equal number of healthy controls was carried out to investigate the association of polymorphism in cytochrome P450 2C19 (CYP2C19), which results in poor and extensive metabolizers (PMs and EMs) genotypes, with squamous cell carcinoma of head and neck (HNSCC) and treatment response in patients receiving combination of chemo-radiotherapy. A higher frequency of CYP2C19 2 variants was observed in the cases resulting in significantly higher risk to HNSCC (Ad OR 3.36, 95% CI 1.94-5.82, p-value<0.05). The PM genotype of CYP2C19 3 was also found to be slightly increased in the cases, though the increase in risk was not significant when analyzed by multivariate logistic regression model. Tobacco chewing amongst the cases resulted in almost 13-fold increase in the risk with CYP2C19 2 (OR: 12.39) and 3-fold with CYP2C19 3 genotype (OR: 2.90) when compared to the tobacco chewers amongst the controls. Likewise, cigarette smoking in the cases increased the risk approximately 9-fold and 3-fold with CYP2C19 2 (OR: 8.93) and CYP2C19 3 (OR: 2.18) genotypes respectively when compared to smokers amongst the controls. Similar increase in risk was associated with alcohol use amongst the cases carrying variant genotypes of CYP2C19 2 (OR: 7.75) or CYP2C19 3 (OR: 2.60), demonstrating the importance of gene-environment interaction in modifying susceptibility to HNSCC. Interestingly, patients with PMs of CYP2C19 (CYP2C19 2 and CYP2C19 3) exhibited little response to the respective chemotherapy than the patients carrying wild-type genotype demonstrating that functional enzyme deficiencies due to polymorphism in CYPs may not only be important in modifying the susceptibility to HNSCC but also in determining chemotherapeutic response.

Association of genetic variability in enzymes metabolizing chemotherapeutic agents with treatment response in head and neck cancer cases.

AIM: The prevalence of genetic variants of thiopurine S-methyltransferse (TPMT) and dihydropyrimidine dehydrogenase (DPD) in healthy controls (500) and the treatment response in 500 cases of head and neck cancer of north Indian origin was studied. METHODS: Blood collected from all the subjects was used for isolation of DNA followed by genotyping studies. The cases received cisplatin and 5-fluorouracil (5-FU) or chemo-radiotherapy and treatment response was measured using WHO criteria. RESULTS: Low frequency of heterozygous mutant genotypes of TPMT*2 (2%), TPMT*3B (2.2%), TPMT*3C (4.6%), DPD IVS14+1G>A (3.6%) and G1601A (3%) was observed, although no homozygous mutants could be identified. Treatment response studies in cases receiving cisplatin and 5-FU or chemo-radiotherapy revealed that the number of nonresponders was higher in cases who carried variant genotypes of TPMT*3B (62.50%) or TPMT*3C (59.26%) or DPD IVS14+1G>A (61.90%). Likewise, the number of nonresponders was still higher in cases carrying combination of these genetic variants. Furthermore, the frequency of nonresponders was higher in cases who carried the variant genotypes of TPMT or DPD and were also tobacco users. CONCLUSIONS: Our data clearly show that TPMT and DPD genes are polymorphic in the north Indian population and may be important in determining the treatment response in cases. The data have also suggest tobacco may play an important role in determining the outcome of cancer therapy and there is an urgent need for assessment of drugs for their efficacy/toxicity in smokers compared to nonsmokers.

Clinical Management of Head and Neck Cancer Cases: Role of Pharmacogenetics of CYP2 and GSTs.

Head and neck squamous cell carcinoma (HNSCC) describes a wide range of malignant tumors which originate in the upper aerodigestive tract and have a multifactorial origin involving both genetic and lifestyle risk factors. The clinical management of head and neck cancer involves surgery, radiotherapy, and chemotherapy. With the advances in treatment strategies for HNSCC, newer targeted therapies are adding to the progress already achieved in the multimodality management of patients although the problems of differences in drug response and adverse drug reactions are still grave concerns. Cancer pharmacogenomics has fast emerged as a new and promising field for the early identification of genetic markers that can predict drug response or toxicity. This could greatly help in identifying genetic markers useful for the selection of optimal drugs, dose, and treatment duration on an individual basis resulting in improved drug efficacy and decreased toxicity. This review focuses on the various treatment modalities available for the clinical management of HNSCC followed by a description of the contribution of genetic variations to chemotherapeutic toxicity and response. Furthermore, studies addressing the association of genetic variants of drug-metabolizing enzymes with treatment response in head and neck cancer are also discussed.

Polymorphism in cytochrome P450 1A2 and their interaction with risk factors in determining risk of squamous cell lung carcinoma in men.

The present case-control study was carried out to investigate the association of functionally important polymorphisms of cytochrome P450 1A2 (CYP1A2) involved in the metabolic activation of tobacco derived procarcinogens with squamous cell carcinoma (SCC) of lung in North Indian men. The study consisted of 200 male cases with SCC of lung and an equal number of age and sex matched healthy controls. Our data showed that variant genotype of CYP1A2*1D and CYP1A2*1F were significantly associated with increased susceptibility to SCC of lung. Likewise, GSTM1 null genotype was found to be over represented in patients when compared to controls. Haplotype analysis revealed that haplotype, G-Tdel-T-C was significantly associated with risk to SCC of lung. Moreover, a significant increase in the risk to SCC of lung in the cases carrying combination of variant genotype of CYP1A2 with either CYP1A1 or GSTM1 have shown that gene-gene interactions may play an important role in squamous cell lung cancer risk. Our data also revealed that smokers or tobacco chewers carrying variant alleles of either CYP1A2*1D or CYP1A2*1F were at increased risk to SCC of lung, further demonstrating that CYP1A2 genotypes interact with environmental risk factors in enhancing the risk to squamous cell lung carcinoma.

Cytochrome P450 2E1 and head and neck cancer: interaction with genetic and environmental risk factors.

The present case-control study investigates the association of polymorphisms in cytochrome P450 2E1 (CYP2E1), involved in the metabolism of tobacco carcinogens and alcohol, with Head and Neck Squamous Cell Carcinoma (HNSCC). In addition, the interaction of CYP2E1 (CYP2E1*5B and CYP2E1*6) with other genetic factors (null genotype of glutathione-S-Transferase M1, GSTM1, X-Ray Repair Cross Complementing Group I, XRCC1 (Arg194Trp), and environmental risk factors such as alcohol and tobacco in modifying HNSCC risk were investigated. Genotypes were determined by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay in a total of 350 male cases of HNSCC and an equal number of healthy male controls. Statistical analysis showed a significant increase in HNSCC risk in cases with variant genotypes of CYP2E1*5B (RsaI) (O.R. 3.44; 95% C.I. 1.45-8.14) and CYP2E1*6 (DraI) (O.R. 1.76; 95% C.I. 1.28-2.41). Haplotype analysis revealed that haplotype T-A was associated with a greater than 10-fold increase in risk for HNSCC. Our data also revealed a several fold increase in HNSCC risk in cases carrying a combination of variant genotypes of CYP2E1 with the null genotype of GSTM1 or XRCC1 variant genotypes. Alcohol or tobacco use (both smoking and chewing) were also found to interact with variant genotypes of CYP2E1 in significantly enhancing HNSCC risk. This increase in risk associated with an interaction of CYP2E1 genotypes with GSTM1 or XRCC1 or with tobacco and alcohol use demonstrates the importance of gene-gene and gene-environment interactions in the development of HNSCC.