Evaluation of the Difference in the Rate of Canine Retraction Assisted by Piezocision and Discission in Human Subjects: A Preliminary Parallel-Arm Prospective Clinical Study.

Objective: The objective of the study was to evaluate the rate of orthodontic tooth movement assisted by piezocision and discission in extraction cases. Methods: Twelve adults (20-35 years) requiring upper premolar extraction for orthodontic treatment were included in this preliminary parallel-arm clinical study. Participants (randomly allocated) in Groups A and B received piezocision and discision-assisted corticotomy cuts at the premolar extraction site, respectively, contralateral side served as the control. Canine retraction was started bilaterally using closed coil NiTi (Nickel titanium) springs. A schedule of fortnightly activation was followed for 3 months. Stage models were made monthly (M0, M1, M2, M3). Models were scanned using a 3-shape intraoral scanner, and the displacement of the canine was measured bilaterally in the stage models. A self-designed questionnaire was used to assess patients pain and satisfaction levels on a visual analogue scale. Results: The rate of canine retraction at the piezocision site was twice that at the control site in group A (p=0.007). The rate of canine retraction at the dissection site was twice that at the control site in group B (p=0.012). However, there was no significant difference in the rate of retraction between the two surgical techniques. Pain and disturbance were noticed in the discission group at 50 and 67% respectively. Conclusion: Discision is comparable to piezocision for accelerating orthodontic tooth movement. Although dissection can speed orthodontic treatment, it should be used with caution as it could pose technical and clinical difficulties, particularly in the posterior buccal region of the oral cavity.

Effect of Ethyl Alcohol Wet Bonding on Shear Bond Strength in Orthodontic Brackets - An In vitro Study.

Aim: To evaluate the effect of ethyl alcohol wet bonding on the shear bond strength of orthodontic brackets. Materials and Methods: 90 premolar teeth were collected and divided into 6 groups - conventional dry, conventional wet, MIP dry, MIP wet, ethanol dry, and ethanol wet. The teeth were bonded as per the requirements for each group. The teeth were then immersed in water to ensure complete polymerization. Shear bond strength was evaluated using a UTM machine and the ARI scores were also noted. Statistical analysis was done for the SBS and ARI scores obtained. Results: The highest SBS was obtained with conventional dry and the least SBS was obtained with conventional wet groups. The SBS of ethanol wet bonding was significantly less than that of the MIP wet group but was significantly more than the conventional wet group. ARI scores also suggested that there is more cohesive failure than adhesive failure in the wet MIP and ethanol groups. Conclusion: The mean SBS (6.5 MPa) was within the optimal bond strength as per the study by Reynolds et al. (1976). Ethanol can be used as a cheaper alternative to MIP.

Survival rate and stability of surface-treated and non-surface-treated orthodontic mini-implants: a randomized clinical trial.

OBJECTIVES: This clinical trial was conducted to evaluate the stability and failure rate of surface-treated orthodontic mini-implants and determine whether they differ from those of non-surface-treated orthodontic mini-implants. TRIAL DESIGN: Randomized clinical trial with a split-mouth study design. SETTING: Department of Orthodontics, SRM Dental College, Chennai. PARTICIPANTS: Patients who required orthodontic mini-implants for anterior retraction in both arches. METHODS: Self-drilling, tapered, titanium orthodontic mini-implants with and without surface treatment were placed in each patient following a split-mouth design. The maximum insertion and removal torques were measured for each implant using a digital torque driver. The failure rates were calculated for each type of mini-implant. RESULTS: The mean maximum insertion torque was 17.9 ± 5.6 Ncm for surface-treated mini-implants and 16.4 ± 9.0 Ncm for non-surface-treated mini-implants. The mean maximum removal torque was 8.1 ± 2.9 Ncm for surface-treated mini-implants and 3.3 ± 1.9 Ncm for non-surface-treated mini-implants. Among the failed implants, 71.4% were non-surface-treated mini-implants and 28.6% were surface-treated mini-implants. CONCLUSION: The insertion torque and failure rate did not differ significantly between the groups, whereas the removal torque was significantly higher in the surface-treated group. Thus, surface treatment using sandblasting and acid etching may improve the secondary stability of self-drilling orthodontic mini-implants. TRIAL REGISTRATION: The trial was registered in the Clinical Trials Registry, India (ICMR NIMS). Registration number: CTRI/2019/10/021718.

Co-Creation of Breast Cancer Risk Communication Tools and an Assessment of Risk Factor Awareness: A Qualitative Study of Patients and the Public in India.

BACKGROUND: Low awareness of BC and its associated risk factors causes delays in diagnosis and impacts survival. It is critical to communicate BC risk to patients in a format that they are easily able to understand. Our study aim was to develop easy-to-follow transmedia prototypes to communicate BC risk and evaluate user preferences, alongside exploring awareness of BC and its risk factors. METHODS: Prototypes of transmedia tools for risk communication were developed with multidisciplinary input. A qualitative in-depth online interview study was undertaken using a pre-defined topic guide of BC patients (7), their relatives (6), the general public (6), and health professionals (6). Interviews were analyzed using a thematic approach. FINDINGS: Most participants preferred pictographic representations (frequency format) of lifetime risk and risk factors and storytelling using short animations and comic strips (infographics) for communicating genetic risk and testing: "In a short time, they explained it very well, and I liked it". Suggestions included minimizing technical terminology, decreasing the delivery speed, "two-way dialogue", and using local "language for different locations". There was low awareness of BC, with some understanding of age and hereditary risk factors but limited knowledge of reproductive factors. INTERPRETATION: Our findings support use of multiple context-specific multimedia tools in communicating cancer risk in an easy-to-understand way. The preference for storytelling using animations and infographics is a novel finding and should be more widely explored.

Streptococcus mutans levels in patients who received orthodontic brackets bonded using probiotic impregnated resin composite - a randomized clinical trial.

To evaluate the effect of impregnating an orthodontic resin composite with probiotic bacteria (Lactobacillus rhamnosus GG) on the levels of Streptococcus mutans (S. mutans) in patients undergoing orthodontic treatment. Thirty patients were randomly selected and allotted by block randomization to two groups: an experimental group, who received brackets bonded with probiotic impregnated resin composite and a control group, who received brackets bonded with conventional light cure resin composite. Plaque samples were collected before (ET0 and CT0) and two months (ET1 and CT1) after bonding. Levels of S. mutans were assessed using the colony count method. Two months after bonding of the brackets, the S. mutans levels had decreased with statistical significance in the experimental group (p = 0.001), but not in the control group (p = 0.137). Impregnation of resin composite with probiotic bacteria for the purpose of preventing formation of white spot lesions on enamel holds promise. Long-term evaluation would be necessary to provide confirmatory results.

Reproducibility of linear and angular cephalometric measurements obtained by an artificial-intelligence assisted software (WebCeph) in comparison with digital software (AutoCEPH) and manual tracing method.

INTRODUCTION: It has been suggested that human errors during manual tracing of linear/angular cephalometric parameters can be eliminated by using computer-aided analysis. The landmarks, however, are located manually and the computer system completes the analysis. With the advent of Artificial Intelligence in the field of Dentistry, automatic location of the landmarks has become a promising tool in digital Orthodontics. METHODS: Fifty pretreatment lateral cephalograms obtained from the Orthodontic department of SRM dental college (India) were used. Analysis were done by the same investigator using the following methods: WebCeph™, AutoCEPH© for Windows or manual tracing. Landmark identification was carried out automatically by Artificial Intelligence in WebCeph™ and with a mouse driven cursor in AutoCEPH©, and manually using acetate sheet and 0.3-mm pencil, ruler and a protractor. The mean differences of the cephalometric parameters obtained between the three methods were calculated using ANOVA with statistical significance set at p<0.05. Intraclass correlation coefficient (ICC) was used to determine both reproducibility and agreement between linear and angular measurements obtained from the three methods and intrarater reliability of repeated measurements. ICC value of >0.75 indicated good agreement. RESULTS: Intraclass correlation coefficient between the three groups was >0.830, showing good level of agreement, and the value within each group was >0.950, indicating high intrarater reliability. CONCLUSION: Artificial Intelligence assisted software showed good agreement with AutoCEPH© and manual tracing for all the cephalometric measurements.

The Effects of Eucalyptus Oil, Glutathione, and Lemon Essential Oil on the Debonding Force, Adhesive Remnant Index, and Enamel Surface During Debonding of Ceramic Brackets.

Objective: The present study aimed to find a chemical reagent that would reduce the debonding force to enable easier debonding of the ceramic brackets, thus reducing enamel damage as well as chair side time. Methods: The study included 4 groups -control (distilled water), eucalyptus oil, glutathione and lemon essential oil for immersing teeth bonded with ceramic brackets. Samples (25 in each group), extracted first premolars, were mounted and immersed in their respective solution for a duration of 10 minutes following which they were tested to evaluate the debonding force using the INSTRON universal testing machine. The amount of adhesive left behind on the enamel surface was evaluated using adhesive remnant index (ARI) score and surface changes were checked using a scanning electron microscope. Results: Teeth immersed in glutathione showed the greatest amount of reduction in debonding force (p=0.001) compared with other groups. ARI scores were low for specimens immersed in glutathione. SEM images showed that teeth in the glutathione group had a cleaner enamel surface, suggesting less or no adhesive was left behind and no sign of enamel damage after debonding ceramic brackets. Conclusion: Specimens that were immersed in glutathione for a duration of 10 minutes before debonding of ceramic brackets showed the greatest reduction in debonding force compared with control and demonstrated peel off effect with no enamel damage. Glutathione can be used as an effective reagent during the clinical debonding of ceramic brackets.

Evaluation and comparison of planum clival angle in three malocclusion groups : A CBCT study.

PURPOSE: Cranial base flexure is an overlooked topic in craniofacial research. The aim of this retrospective observational study was to compare a new parameter, the planum clival angle (PCA), which represents cranial base flexure, in skeletal class I, II, and III malocclusions using cone beam computed tomographic images (CBCT) and correlate PCA with the stages of the fusion of the spheno-occipital synchondrosis (SOS). MATERIALS AND METHODS: A total of 125 CBCTs were divided into two groups based on chronological age (19-25 years and 12-18 years). The CBCT images from 57 subjects (19-25 years old) were categorized into three groups based on their skeletal malocclusion for measuring PCA and cranial base angles (CBA). In the second group, comprising 68 CBCT data sets of individuals in the age group of 12-18 years, the PCA angle was correlated with stages of fusion of the SOS. Data were statistically analyzed using independent samples t test, one-way analysis of variance (ANOVA, intergroup), Pearson correlation, and χ2 test. RESULTS: There was a statistically significant linear correlation (P < 0.001) between the two parameters PCA and CBA but no significant difference was found in PCAs between the three groups. One-way ANOVA to compare the PCA values in the three stages of fusion of the SOS revealed a highly significant relationship in male subjects (p < 0.001), thereby, suggesting that as fusion progresses, the planum clival angle increases. The χ2 test to compare the planum clival angle in males and females revealed that SOS fusion occurred earlier in females. CONCLUSION: There is a constant dynamic change in the value of the parameter PCA that progresses until completion of SOS fusion. The SOS fuses earlier in females. Assessment of the stage of fusion of the SOS can be used in deciding whether growth modification of the craniofacial complex is still possible during orthodontic therapy.

National Cancer Grid Virtual Tumor Boards of Head and Neck Cancers: An Innovative Approach to Multidisciplinary Care.

PURPOSE: Virtual tumor board (VTB) via videoconference facility involving multiple specialists in the decision making for various tumors is well accepted, especially in high-income countries. Information on virtual tumor boards for head and neck cancers especially from low- and middle-income countries is sparse. In this study, we have audited the findings of the National Cancer Grid VTBs performed for head and neck cancers. METHODS: All patients discussed in the head and neck VTBs at our center between December 2016 and February 2022 were included in the study. Details such as the type of institute sending patients for discussion, its location, subsites within the head and neck region, histopathology, treatment setting or question for the VTB, and availability of guidelines for such patient scenarios were assessed. Also, a survey was sent to assess the usefulness of the VTBs. RESULTS: A total of 208 patients were discussed in 54 VTB sessions. The most common head and neck sites discussed in the VTBs were the oral cavity (n = 64, 30.7%) followed by skull base/nose and paranasal sinuses/eyelid-orbit tumors (n = 49, 23.5%). Nonsquamous cell carcinoma was the most common histopathology discussed; recurrent cancers/residual diseases were the most common treatment settings (n = 134, 64.4%) for which there were no existing guidelines. Survey results showed that most VTB decisions were implementable, and respondents felt that VTBs were a useful educational tool as well. CONCLUSION: Our study affirms the feasibility of VTBs in low- and middle-income countries' health care systems for managing uncommon malignancies and clinical situations, which act as an important educational platform.

Survival rate and stability of surface-treated and non-surface-treated orthodontic mini-implants: a randomized clinical trial

ABSTRACT Objectives: This clinical trial was conducted to evaluate the stability and failure rate of surface-treated orthodontic mini-implants and determine whether they differ from those of non-surface-treated orthodontic mini-implants. Trial Design: Randomized clinical trial with a split-mouth study design. Setting: Department of Orthodontics, SRM Dental College, Chennai. Participants: Patients who required orthodontic mini-implants for anterior retraction in both arches. Methods: Self-drilling, tapered, titanium orthodontic mini-implants with and without surface treatment were placed in each patient following a split-mouth design. The maximum insertion and removal torques were measured for each implant using a digital torque driver. The failure rates were calculated for each type of mini-implant. Results: The mean maximum insertion torque was 17.9 ± 5.6 Ncm for surface-treated mini-implants and 16.4 ± 9.0 Ncm for non-surface-treated mini-implants. The mean maximum removal torque was 8.1 ± 2.9 Ncm for surface-treated mini-implants and 3.3 ± 1.9 Ncm for non-surface-treated mini-implants. Among the failed implants, 71.4% were non-surface-treated mini-implants and 28.6% were surface-treated mini-implants. Conclusion: The insertion torque and failure rate did not differ significantly between the groups, whereas the removal torque was significantly higher in the surface-treated group. Thus, surface treatment using sandblasting and acid etching may improve the secondary stability of self-drilling orthodontic mini-implants. Trial registration: The trial was registered in the Clinical Trials Registry, India (ICMR NIMS). Registration number: CTRI/2019/10/021718

RESUMO Objetivos: Este ensaio clínico foi conduzido para avaliar a estabilidade e a taxa de falha de mini-implantes ortodônticos com superfície tratada, e determinar se elas diferem das dos mini-implantes ortodônticos sem superfície tratada. Desenho do estudo: Ensaio clínico randomizado com desenho de boca dividida. Instituição: Department of Orthodontics, SRM Dental College, Chennai/India. Participantes: Pacientes que necessitavam de mini-implantes ortodônticos para retração anterior em ambas as arcadas. Métodos: Mini-implantes ortodônticos autoperfurantes, cônicos, de titânio com ou sem tratamento de superfície, foram colocados em cada paciente, seguindo um desenho de boca dividida. Os torques máximos de inserção e de remoção foram medidos para cada mini-implante, usando um torquímetro digital. As taxas de falha foram calculadas para cada tipo de mini-implante. Resultados: O valor médio do torque máximo de inserção foi de 17,9 ± 5,6 Ncm para mini-implantes com superfície tratada e 16,4 ± 9,0 Ncm para mini-implantes sem superfície tratada. O valor médio do torque máximo de remoção foi de 8,1 ± 2,9 Ncm para mini-implantes com superfície tratada e 3,3 ± 1,9 Ncm para mini-implantes sem superfície tratada. Entre os implantes que falharam, 71,4% eram mini-implantes sem superfície tratada e 28,6% eram mini-implantes com superfície tratada. Conclusão: O torque de inserção e a taxa de falha não diferiram significativamente entre os grupos; porém, o torque de remoção foi significativamente maior no grupo com superfície tratada. Assim, o tratamento de superfície com jateamento e condicionamento ácido pode melhorar a estabilidade secundária dos mini-implantes ortodônticos autoperfurantes. Registro do estudo: Esse estudo foi registrado no Clinical Trials Registry, Índia (ICMR NIMS). Número de registro: CTRI/2019/10/021718

Reproducibility of linear and angular cephalometric measurements obtained by an artificial-intelligence assisted software (WebCeph) in comparison with digital software (AutoCEPH) and manual tracing method

ABSTRACT Introduction: It has been suggested that human errors during manual tracing of linear/angular cephalometric parameters can be eliminated by using computer-aided analysis. The landmarks, however, are located manually and the computer system completes the analysis. With the advent of Artificial Intelligence in the field of Dentistry, automatic location of the landmarks has become a promising tool in digital Orthodontics. Methods: Fifty pretreatment lateral cephalograms obtained from the Orthodontic department of SRM dental college (India) were used. Analysis were done by the same investigator using the following methods: WebCeph™, AutoCEPH© for Windows or manual tracing. Landmark identification was carried out automatically by Artificial Intelligence in WebCeph™ and with a mouse driven cursor in AutoCEPH©, and manually using acetate sheet and 0.3-mm pencil, ruler and a protractor. The mean differences of the cephalometric parameters obtained between the three methods were calculated using ANOVA with statistical significance set at p<0.05. Intraclass correlation coefficient (ICC) was used to determine both reproducibility and agreement between linear and angular measurements obtained from the three methods and intrarater reliability of repeated measurements. ICC value of >0.75 indicated good agreement. Results: Intraclass correlation coefficient between the three groups was >0.830, showing good level of agreement, and the value within each group was >0.950, indicating high intrarater reliability. Conclusion: Artificial Intelligence assisted software showed good agreement with AutoCEPH© and manual tracing for all the cephalometric measurements.

RESUMO Introdução: Tem sido sugerido que os erros humanos durante o traçado manual das medidas cefalométricas lineares/angulares podem ser eliminados usando a análise guiada por computador. Os pontos de referência, no entanto, são localizados manualmente e o sistema computadorizado completa a análise. Com o advento da Inteligência Artificial na Odontologia, a localização automática dos pontos de referência tornou-se uma ferramenta promissora na Ortodontia digital. Métodos: Cinquenta cefalogramas laterais pré-tratamento obtidos do departamento de Ortodontia da Faculdade de Odontologia SRM (Índia) foram usados. Todas as análises foram feitas pelo mesmo investigador, usando os seguintes métodos: WebCeph™, AutoCEPH© para Windows ou traçado manual. A identificação dos pontos foi realizada automaticamente por Inteligência Artificial no WebCeph™; com o cursor do mouse, no AutoCEPH©; e manualmente, utilizando folha de acetato e lápis 0,3 mm, régua e transferidor. As diferenças médias dos parâmetros cefalométricos entre os três métodos foram calculadas por ANOVA com significância estatística fixada em p<0,05. O coeficiente de correlação intraclasse (ICC) foi usado para determinar a reprodutibilidade e a concordância entre as medidas lineares e angulares obtidas pelos três métodos e a confiabilidade intraexaminador para medidas repetidas. O valor de ICC > 0,75 indicou boa concordância. Resultados: O ICC entre os três grupos foi >0,830, mostrando bom nível de concordância, e o valor dentro de cada grupo foi >0,950, indicando alta confiabilidade intra-avaliador. Conclusão: O software assistido por Inteligência Artificial mostrou boa concordância com o AutoCEPH© e o traçado manual para todas as medidas cefalométricas.

Evaluation and comparison of stresses and displacements generated by four different types of asymmetric maxillary expansion appliances in true unilateral crossbite using finite element method.

INTRODUCTION: True unilateral posterior crossbite can be efficiently treated by using asymmetric expansion appliances that essentially exert unilateral expansion forces thereby minimizing iatrogenic overexpansion of the normal pretreatment side. AIM: To evaluate and compare the stresses and displacements generated by four different types of asymmetric maxillary expansion appliances in true unilateral crossbite using the finite element method. MATERIALS AND METHODS: A CBCT image of the skull was obtained from a 12-year-old female patient with a true unilateral posterior crossbite on the right side, for the FEM study. Asymmetrically split acrylic plate with jackscrew (ASAPJ), NORD crossbite expander, Asymmetric Maxillary Expansion appliance (AMEX), Asymmetrical Rapid Maxillary Expansion (ARME) appliances were simulated with a given force specific to the appliance. Von Mises stresses, displacements in the x, y, z-axis, and changes in the axial inclination were evaluated and compared on the selected skeletal and dental landmarks. RESULTS: Overall ARME seemed to generate the highest asymmetric von Misses stress on skeletal landmarks followed by NORD; ASAPJ and lowest by the AMEX. ARME also produced the highest asymmetric expansion followed by AMEX; NORD and lowest with the ASAPJ. NORD produced the minimum extrusion and buccal tipping of the canine and 1st molar followed by ASAPJ; AMEX and maximum by the ARME. CONCLUSION: Each of the four appliances expanded the maxillary arch more on the crossbite side as compared to the non-crossbite side, but the pattern of stress distribution, displacement and change in the axial inclination were unique for each appliance.

Effect of placement angle, diameter, length and bone density on the pull-out strength of orthodontic mini-implants: An in vitro study.

OBJECTIVE: To evaluate the effect of the placement angle, diameter, length and bone density on the mechanical stability of orthodontic mini-implants by measuring their pull-out strengths. DESIGN: A total of 120 mini-implants of four different dimensions made from titanium were used. They measured 1.3 × 6.0mm, 1.3 × 8.0 mm, 1.5 × 6.0 mm and 1.5 × 8.0 mm. Synthetic polyurethane bone blocks (Saw Bones, USA) in two different densities were used. SETTING: Each size of mini-implant was inserted equidistantly into synthetic bone blocks of two different densities, in three different insertion angles of 30°, 60° and 90°. This resulted in 24 test groups with five mini-implants allocated to each group. METHODS: The pull-out strength was measured using an Instron Universal Testing Machine exerting a vertical force parallel to the long axis of the mini-implant until removal or failure occurred. Peak load at failure of the mini-implant was recorded in kN. RESULTS: Showed that mini-implants placed at an insertion angle of 30° offered least resistance to pull-out. Mini-implants 6.0 mm in length showed less pull-out strength compared to the longer 8.0-mm mini-implants. Mini-implants 1.3 mm in diameter provided similar pull-out values as 1.5-mm mini-implants. Bone densities of 0.20 g/cc and 0.32 g/cc did not affect the pull-out strength of mini-implants. CONCLUSION: From the study, it was concluded that a logical choice of mini-implant dimension and prudent use of placement technique can help achieve the treatment goals with a reduced hazard of mini-implant failure.

Barriers and facilitators in implementing population based common cancer screening through community health workers.

Population based cancer screening was initiated in India in 2016 owing to an increased burden of cancers. A feasibility health system study was done by utilising community health workers (CHWs) to conduct the cancer screening. The current study is a qualitative study to elicit the barriers and facilitators in implementing population based cancer screening through CHWs. The study was conducted at three subcentres of Dholai block of Cachar district, Assam, India and Cachar Cancer Hospital and Research Center, Silchar. The participants of the study were CHWs, master trainer nurses and women from community. Three focus group discussions (FGDs) and one in-depth interview (IDI) were conducted at the provider level and seven IDIs of women from the community. The FGDs and IDIs were audio recorded after taking verbal consent from the participants. The verbatims were prepared following translation and transcription and data analysis using ATLAS ti ver 8. The major barrier faced by the community was a lack of motivation to get screened which stemmed from various factors such as personal beliefs, attitudes and fear. The major facilitators were accessibility of tests, family support and CHWs as screening service providers. The major barriers for CHWs were difficulty in motivating the community, lack of support from supervisors and lack of motivation to work. The major facilitators were convenience of screening during home visits, empowerment, skill enhancement and teamwork. Population based cancer screening was a new concept for the community under study. Cancer screening by CHWs was well accepted by the community. Awareness generation among the community was a major factor in improving screening coverage. The study highlights that training and motivation of CHWs can improve the uptake of cancer screening services. CHWs felt empowered with the new skills imparted and were able to carry out screening.

Lifestyle chemical carcinogens associated with mutations in cell cycle regulatory genes increases the susceptibility to gastric cancer risk.

In the present study, we correlated the various lifestyle habits and their associated mutations in cell cycle (P21 and MDM2) and DNA damage repair (MLH1) genes to investigate their role in gastric cancer (GC). Multifactor dimensionality reduction (MDR) analysis revealed the two-factor model of oral snuff and smoked meat as the significant model for GC risk. The interaction analysis between identified mutations and the significant demographic factors predicted that oral snuff is significantly associated with P21 3'UTR mutations. A total of five mutations in P21 gene, including three novel mutations in intron 2 (36651738G > A, 36651804A > T, 36651825G > T), were identified. In MLH1 gene, two variants were identified viz. one in exon 8 (37053568A > G; 219I > V) and a novel 37088831C > G in intron 16. Flow cytometric analysis predicted DNA aneuploidy in 07 (17.5%) and diploidy in 33 (82.5%) tumor samples. The G2/M phase was significantly arrested in aneuploid gastric tumor samples whereas high S-phase fraction was observed in all the gastric tumor samples. This study demonstrated that environmental chemical carcinogens along with alteration in cell cycle regulatory (P21) and mismatch repair (MLH1) genes may be stimulating the susceptibility of GC by altering the DNA content level abnormally in tumors in the Mizo ethic population.

Association of DFNA5, SYK, and NELL1 variants along with HPV infection in oral cancer among the prolonged tobacco-chewers.

Southeast Asia, especially India, is well known for the highest use of smokeless tobacco. These products are known to induce oral squamous cell carcinoma. However, not all long-term tobacco-chewers develop oral squamous cell carcinoma. In addition, germline variants play a crucial role in susceptibility, prognosis, development, and progression of the disease. These prompted us to study the genetic susceptibility to oral squamous cell carcinoma among the long-term tobacco-chewers. Here, we presented a retrospective study on prolonged tobacco-chewers of Northeast India to identify the potential protective or risk-associated germline variants in tobacco-related oral squamous cell carcinoma along with HPV infection. Targeted re-sequencing (n = 60) of 170 genetic regions from 75 genes was carried out in Ion-PGM™ and validation (n = 116) of the observed variants was done using Sequenom iPLEX MassARRAY™ platform followed by polymerase chain reaction-based HPV genotyping and p16-immunohistochemistry study. Subsequently, estimation of population structure, different statistical and in silico approaches were undertaken. We identified one nonsense-mediated mRNA decay transcript variant in the DFNA5 region (rs2237306), associated with Benzo(a)pyrene, as a protective factor (odds ratio = 0.33; p = 0.009) and four harmful (odds ratio > 2.5; p < 0.05) intronic variants, rs182361, rs290974, and rs169724 in SYK and rs1670661 in NELL1 region, involved in genetic susceptibility to tobacco- and HPV-mediated oral oncogenesis. Among the oral squamous cell carcinoma patients, 12.6% (11/87) were HPV positive, out of which 45.5% (5/11) were HPV16-infected, 27.3% (3/11) were HPV18-infected, and 27.3% (3/11) had an infection of both subtypes. Multifactor dimensionality reduction analysis showed that the interactions among HPV and NELL1 variant rs1670661 with age and gender augmented the risk of both non-tobacco- and tobacco-related oral squamous cell carcinoma, respectively. These suggest that HPV infection may be one of the important risk factors for oral squamous cell carcinoma in this population. Finally, we newly report a DFNA5 variant probably conferring protection via nonsense-mediated mRNA decay pathway against tobacco-related oral squamous cell carcinoma. Thus, the analytical approach used here can be useful in predicting the population-specific significant variants associated with oral squamous cell carcinoma in any heterogeneous population.