Displaying publications 161 - 180 of 211 in total

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  1. Ariffin H, Chan AS, Oh L, Abd-Ghafar S, Ong GB, Mohamed M, et al.
    Clin Genet, 2015 Nov;88(5):450-5.
    PMID: 25318593 DOI: 10.1111/cge.12525
    Type of cancer and age of onset in individuals with inherited aberrations in the tumour suppressor gene TP53 are variable, possibly influenced by genetic modifiers and different environmental exposure. Since 2009, the modified Chompret criteria (MCC) have been used to identify individuals for TP53 mutation screening. Using the TP53 mutation database maintained by the International Agency for Research on Cancer (IARC), we investigated if the MCC, mainly developed for a Caucasian population, was also applicable in Asia. We identified several differences in Asian families compared with similar Caucasian cohorts, suggesting that identification and management of Li-Fraumeni syndrome in Asia do not completely mirror that of North America and Western Europe. Early gastric cancer (<40 years) may be considered a new addition to the MCC especially for Asian families.
  2. Balakrishnan N, Teo SH, Sinnadurai S, Bhoo Pathy NT, See MH, Taib NA, et al.
    World J Surg, 2017 11;41(11):2735-2745.
    PMID: 28653143 DOI: 10.1007/s00268-017-4081-9
    BACKGROUND: Reproductive factors are associated with risk of breast cancer, but the association with breast cancer survival is less well known. Previous studies have reported conflicting results on the association between time since last childbirth and breast cancer survival. We determined the association between time since last childbirth (LCB) and survival of women with premenopausal and postmenopausal breast cancers in Malaysia.

    METHOD: A historical cohort of 986 premenopausal, and 1123 postmenopausal, parous breast cancer patients diagnosed from 2001 to 2012 in University Malaya Medical Centre were included in the analyses. Time since LCB was categorized into quintiles. Multivariable Cox regression was used to determine whether time since LCB was associated with survival following breast cancer, adjusting for demographic, tumor, and treatment characteristics.

    RESULTS: Premenopausal breast cancer patients with the most recent childbirth (LCB quintile 1) were younger, more likely to present with unfavorable prognostic profiles and had the lowest 5-year overall survival (OS) (66.9; 95% CI 60.2-73.6%), compared to women with longer duration since LCB (quintile 2 thru 5). In univariable analysis, time since LCB was inversely associated with risk of mortality and the hazard ratio for LCB quintile 2, 3, 4, and 5 versus quintile 1 were 0.53 (95% CI 0.36-0.77), 0.49 (95% CI 0.33-0.75), 0.61 (95% CI 0.43-0.85), and 0.64 (95% CI 0.44-0.93), respectively; P trend = 0.016. However, this association was attenuated substantially following adjustment for age at diagnosis and other prognostic factors. Similarly, postmenopausal breast cancer patients with the most recent childbirth were also more likely to present with unfavorable disease profiles. Compared to postmenopausal breast cancer patients in LCB quintile 1, patients in quintile 5 had a higher risk of mortality. This association was not significant following multivariable adjustment.

    CONCLUSION: Time since LCB is not independently associated with survival in premenopausal or postmenopausal breast cancers. The apparent increase in risks of mortality in premenopausal breast cancer patients with a recent childbirth, and postmenopausal patients with longer duration since LCB, appear to be largely explained by their age at diagnosis.

  3. Ng PS, Wen WX, Fadlullah MZ, Yoon SY, Lee SY, Thong MK, et al.
    Clin Genet, 2016 10;90(4):315-23.
    PMID: 26757417 DOI: 10.1111/cge.12735
    Although an association between protein-truncating variants and breast cancer risk has been established for 11 genes, only alterations in BRCA1, BRCA2, TP53 and PALB2 have been reported in Asian populations. Given that the age of onset of breast cancer is lower in Asians, it is estimated that inherited predisposition to breast cancer may be more significant. To determine the potential utility of panel testing, we investigated the prevalence of germline alterations in 11 established and 4 likely breast cancer genes in a cross-sectional hospital-based cohort of 108 moderate to high-risk breast cancer patients using targeted next generation sequencing. Twenty patients (19%) were identified to carry deleterious mutations, of whom 13 (12%) were in the BRCA1 or BRCA2, 6 (6%) were in five other known breast cancer predisposition genes and 1 patient had a mutation in both BRCA2 and BARD1. Our study shows that BRCA1 and BRCA2 account for the majority of genetic predisposition to breast cancer in our cohort of Asian women. Although mutations in other known breast cancer genes are found, the functional significance and breast cancer risk have not yet been determined, thus limiting the clinical utility of panel testing in Asian populations.
  4. Soh WH, Rajaram N, Mariapun S, Eriksson M, Fadzli F, Ho WK, et al.
    Cancer Causes Control, 2018 Sep;29(9):883-894.
    PMID: 30062608 DOI: 10.1007/s10552-018-1064-6
    BACKGROUND: Physical activity is a modifiable lifestyle factor associated with reduced breast cancer risk. Mammographic density is a strong, independent risk factor for breast cancer, and some breast cancer risk factors have been shown to modify mammographic density. However, the effect of physical activity on mammographic density, studied predominantly among Caucasians, has yielded conflicting results. In this study, we examined, in an Asian population, the association between physical activity and mammographic density.

    METHODS: We conducted a cross-sectional study of 2,377 Malaysian women aged 40-74 years. Physical activity information was obtained at screening mammogram and mammographic density was measured from mammograms by the area-based STRATUS method (n = 1,522) and the volumetric Volpara™ (n = 1,200) method. Linear regression analyses were performed to evaluate the association between physical activity and mammographic density, adjusting for potential confounders.

    RESULTS: We observed that recent physical activity was associated with area-based mammographic density measures among postmenopausal women, but not premenopausal women. In the fully adjusted model, postmenopausal women with the highest level of recent physical activity had 8.0 cm2 [95% confidence interval: 1.3, 14.3 cm2] lower non-dense area and 3.1% [0.1, 6.3%] higher area-based percent density, compared to women with the lowest level of recent physical activity. Physical activity was not associated to volumetric mammographic density.

    CONCLUSIONS: Our findings suggest that the beneficial effects of physical activity on breast cancer risk may not be measurable through mammographic density. Future research is needed to identify appropriate biomarkers to assess the effect of physical activity on breast cancer risk.

  5. Lai KN, Ho WK, Kang IN, Kang PC, Phuah SY, Mariapun S, et al.
    BMC Cancer, 2017 02 22;17(1):149.
    PMID: 28222693 DOI: 10.1186/s12885-017-3099-6
    BACKGROUND: Genetic testing for BRCA1 and BRCA2 has led to the accurate identification of individuals at higher risk of cancer and the development of new therapies. Approximately 10-20% of the genetic testing for BRCA1 and BRCA2 leads to the identification of variants of uncertain significance (VUS), with higher proportions in Asians. We investigated the functional significance of 7 BRCA1 and 25 BRCA2 variants in a multi-ethnic Asian cohort using a case-control approach.

    METHODS: The MassARRAY genotyping was conducted in 1,394 Chinese, 406 Malay and 310 Indian breast cancer cases and 1,071 Chinese, 167 Malay and 255 Indian healthy controls. The association of individual variant with breast cancer risk was analyzed using logistic regression model adjusted for ethnicity, age and family history.

    RESULTS: Our study confirmed BRCA2 p.Ile3412Val is presented in >2% of unaffected women and is likely benign, and BRCA2 p.Ala1996Thr which is predicted to be likely pathogenic by in-silico models is presented in 2% of healthy Indian women suggesting that it may not be associated with breast cancer risk. Single-variant analysis suggests that BRCA1 p.Arg762Ser may be associated with breast cancer risk (OR = 7.4; 95% CI, 0.9-62.3; p = 0.06).

    CONCLUSIONS: Our study shows that BRCA2 p.Ile3412Val and p.Ala1996Thr are likely benign and highlights the need for population-specific studies to determine the likely functional significance of population-specific variants. Our study also suggests that BRCA1 p.Arg762Ser may be associated with increased risk of breast cancer but other methods or larger studies are required to determine a more precise estimate of breast cancer risk.

  6. Lee DS, Meiser B, Mariapun S, Hassan T, Yip CH, Mohd Taib NA, et al.
    J Genet Couns, 2021 Jun;30(3):720-729.
    PMID: 33245177 DOI: 10.1002/jgc4.1360
    The vast majority of studies assessing communication of BRCA1/2 results with relatives and family uptake of BRCA1/2 testing have been conducted in Western societies, and a dearth of studies have been conducted in Asia among relatives of diverse carriers of pathogenic BRCA1/2 germline variants. This study aimed to present rates of BRCA1/2 result disclosure by probands and probands' motivators and barriers of family communication and predictive testing uptake among eligible relatives. It also examined patterns of disclosure and testing uptake among different types of relatives. Eighty-seven carriers with either breast or ovarian cancer, who had previously been found to be carriers of a pathogenic variant in BRCA1/2, were interviewed over the phone using a semi-structured interview guide. Fifty-six percent of patients were Chinese, 21% were Indian, and 23% were Malay. It was found that 62.0% of eligible first- and second-degree relatives were informed by the proband about the testing result and that 11.5% of eligible first- and second-degree relatives had genetic testing. First-degree relatives were more likely to have been informed and tested compared to second-degree relatives, as were sisters compared to brothers. The low rates of family communication and testing uptake documented in this study suggest that interventions should focus on encouraging probands to inform male and second-degree relatives and targeting such relatives to increase informed decisions and accessibility to testing. Promotion strategies should be culturally sensitive to optimize outcomes.
  7. Malekbala MR, Soltani S, Abdul Rashid S, Abdullah LC, Rashid U, Nehdi IA, et al.
    Materials (Basel), 2020 Apr 10;13(7).
    PMID: 32290065 DOI: 10.3390/ma13071775
    In the present study, a sequence of experiments was performed to assess the influence of the key process parameters on the formation of a carbon nanofiber-coated monolith (CNFCM), using a four-level factorial design in response surface methodology (RSM). The effect of reaction temperature, hydrocarbon flow rate, catalyst and catalyst promoter were examined using RSM to enhance the formation yield of CNFs on a monolith substrate. To calculate carbon yield, a quadratic polynomial model was modified through multiple regression analysis and the best possible reaction conditions were found as follows: a reaction temperature of 800 °C, furfuryl alcohol flow of 0.08525 mL/min, ferrocene catalyst concentration of 2.21 g. According to the characterization study, the synthesized CNFs showed a high graphitization which were uniformly distributed on a monolith substrate. Besides this, the feasibility of carbon dioxide (CO2) adsorption from the gaseous mixture (N2/CO2) under a range of experimental conditions was investigated at monolithic column. To get the most out of the CO2 capture, an as-prepared sample was post-modified using ammonia. Furthermore, a deactivation model (DM) was introduced for the purpose of studying the breakthrough curves. The CO2 adsorption onto CNFCM was experimentally examined under following operating conditions: a temperature of 30-50 °C, pressure of 1-2 bar, flow rate of 50-90 mL/min, and CO2 feed amount of 10-40 vol.%. A lower adsorption capacity and shorter breakthrough time were detected by escalating the temperature. On the other hand, the capacity for CO2 adsorption increased by raising the CO2 feed amount, feed flow rate, and operating pressure. The comparative evaluation of CO2 uptake over unmodified and modified CNFCM adsorbents confirmed that the introduced modification procedure caused a substantial improvement in CO2 adsorption.
  8. Islam A, Teo SH, Ahmed MT, Khandaker S, Ibrahim ML, Vo DN, et al.
    Chemosphere, 2021 Jun;272:129653.
    PMID: 33486455 DOI: 10.1016/j.chemosphere.2021.129653
    The contamination of groundwater by arsenic (As) in Bangladesh is the biggest impairing of a population, with a large number of peoples affected. Specifically, groundwater of Gangetic Delta is alarmingly contaminated with arsenic. Similar, perilous circumstances exist in many other countries and consequently, there is a dire need to develop cost-effective decentralized filtration unit utilizing low-cost adsorbents for eliminating arsenic from water. Morphological synthesis of carbon with unique spherical, nanorod, and massive nanostructures were achieved by solvothermal method. Owing to their intrinsic adsorption properties and different nanostructures, these nanostructures were employed as adsorption of arsenic in aqueous solution, with the purpose to better understanding the morphological effect in adsorption. It clearly demonstrated that carbon with nanorods morphology exhibited an excellent adsorption activity of arsenite (about 82%) at pH 3, remarkably superior to the two with solid sphere and massive microstructures, because of its larger specific surface area, enhanced acid strength and improved adsorption capacity. Furthermore, we discovered that iron hydroxide radicals and energy-induced contact point formation in nanorods are the responsible for the high adsorption of As in aqueous solution. Thus, our work provides insides into the microstructure-dependent capability of different carbon for As adsorption applications.
  9. Teo SH, Ong TK, Merican AM, Hashim MS, Ng WM, Al-Fayyadh MZM, et al.
    Indian J Orthop, 2023 Jun;57(6):847-855.
    PMID: 37214363 DOI: 10.1007/s43465-023-00874-x
    BACKGROUND: Accurate planning for patellar instability correction is important in obtaining good post-operative outcome. The main challenge in the current two-dimensional (2-D) computed tomographic (CT) scans method is the difficulty in choosing reliable bony landmarks. This study aimed to compare the reliabilities between the 2-D and three-dimensional (3-D) methods of measuring tibial tubercle-trochlear groove (TT-TG) distance. We hypothesize that the proposed 3-D method will result in measurements with narrower error margin, providing higher reliability and accuracy.

    MATERIALS AND METHODS: We traced CT scans of 106 knees with no patellofemoral pathology from 59 subjects from the database system and converted all 2-D images into 3-D models to determine the values for each parameter. We compared the intra- and interobserver reliability of each method using intraclass correlation (ICC) and Bland-Altman method.

    RESULTS: The values of TT-TG measured by 2-D and 3-D methods were 16.1 ± 4.6 mm and 16.2 ± 4.2 mm, respectively. The ICC values of both methods were comparable (95% limits of agreement between the same observer: - 3.3 to 3.8 mm versus - 2.4 to 2.7 mm and different observers: - 4.3 to 4.9 mm versus - 3.9 to 2.7 mm), with 3-D method results in narrower limits of agreement.

    CONCLUSION: TT-TG measurement is reliable using the 2-D method without using advanced radiographic software. The 3-D method of measuring TT-TG provides measurement with narrower variation when compared with the 2-D method. However, both TT-TG distances' measurement methods in the current study were comparable as the variations are not significant.

  10. Mariapun S, Ho WK, Kang PC, Li J, Lindström S, Yip CH, et al.
    Cancer Epidemiol Biomarkers Prev, 2016 Feb;25(2):327-33.
    PMID: 26677210 DOI: 10.1158/1055-9965.EPI-15-0746
    Mammographic density is an established risk factor for breast cancer and has a strong heritable component. Genome-wide association studies (GWAS) for mammographic density conducted in women of European descent have identified several genetic associations, but none of the studies have been tested in Asians. We sought to investigate whether these genetic loci, and loci associated with breast cancer risk and breast size, are associated with mammographic density in an Asian cohort.
  11. Mariapun S, Li J, Yip CH, Taib NA, Teo SH
    PLoS One, 2015;10(2):e0117568.
    PMID: 25659139 DOI: 10.1371/journal.pone.0117568
    BACKGROUND: Mammographic density is a strong risk factor for breast cancer and is highly variable, but, to date, few studies have examined density in Asian women, particularly those in low and middle-income Asian countries where genetic and lifestyle determinants may be significantly different.
    METHODS: A total of 1,240 women who attended an opportunistic mammogram screening programme were eligible for analysis. Mammographic density was estimated using a fully-automated thresholding method and differences across ethnic groups were examined using linear regression in 205 randomly selected Chinese women, 138 Malay and 199 Indian women.
    RESULTS: Percent density was significantly higher in Chinese women (28.5%; 95% CI 27.0%, 30.0%) compared to Malay (24.2%; 95% CI 22.5%, 26.0%) and Indian (24.3%; 95% CI 22.8%, 25.7%) women (p<0.001), after adjustment for age, BMI, menopausal status, parity and age at first full term pregnancy. Correspondingly, adjusted nondense area was significantly lower in Chinese (72.2cm2; 95% CI 67.9cm2, 76.5cm2) women compared to Malay (92.1cm2; 95% CI 86.9cm2, 97.2cm2) and Indian (97.7cm2; 95% CI 93.4cm2, 101.9cm2) women (p<0.001), but dense area did not differ across the three ethnic groups.
    CONCLUSIONS: Our study shows that higher percent density and lower nondense area reflect the higher incidence of breast cancer in Chinese compared to Malay and Indian women in Malaysia. Known lifestyle determinants of mammographic density do not fully account for the ethnic variations observed in mammographic density in this Asian cohort.
  12. Abdullah A, Abdullah KL, Yip CH, Teo SH, Taib NA, Ng CJ
    Asian Pac J Cancer Prev, 2013;14(12):7143-7.
    PMID: 24460266
    BACKGROUND: The survival outcomes for women presenting with early breast cancer are influenced by treatment decisions. In Malaysia, survival outcome is generally poor due to late presentation. Of those who present early, many refuse treatment for complementary therapy.
    OBJECTIVE: This study aimed to explore the decision making experiences of women with early breast cancer.
    MATERIALS AND METHODS: A qualitative study using individual in-depth interviews was conducted to capture the decision making process of women with early breast cancer in Malaysia. We used purposive sampling to recruit women yet to undergo surgical treatment. A total of eight participants consented and were interviewed using a semi-structured interview guide. These women were recruited from a period of one week after they were informed of their diagnoses. A topic guide, based on the Ottawa decision support framework (ODSF), was used to facilitate the interviews, which were audio recorded, transcribed and analysed using a thematic approach.
    RESULTS: We identified four phases in the decision-making process of women with early breast cancer: discovery (pre-diagnosis); confirmatory ('receiving bad news'); deliberation; and decision (making a decision). These phases ranged from when women first discovered abnormalities in their breasts to them making final surgical treatment decisions. Information was vital in guiding these women. Support from family members, friends, healthcare professionals as well as survivors also has an influencing role. However, the final say on treatment decision was from themselves.
    CONCLUSIONS: The treatment decision for women with early breast cancer in Malaysia is a result of information they gather on their decision making journey. This journey starts with diagnosis. The women's spouses, friends, family members and healthcare professionals play different roles as information providers and supporters at different stages of treatment decisions. However, the final treatment decision is influenced mainly by women's own experiences, knowledge and understanding.
    Study site: Breast surgical units, Klang Valley, Malaysia
  13. Ee GC, Teo SH, Rahmani M, Lim CK, Lim YM, Go R
    Nat Prod Res, 2011 Jun;25(10):995-1003.
    PMID: 21644180 DOI: 10.1080/14786419.2010.534471
    A new furanodihydrobenzoxanthone, artomandin (1), together with three other flavonoid derivatives, artoindonesianin C, artonol B, and artochamin A, as well as β-sitosterol were isolated from the stem bark of Artocarpus kemando. The structures of these compounds were determined on the basis of spectral evidence. All of these compounds displayed inhibition effects to a very susceptible degree in cancer cell line tests. Compound 1 also exhibited significant antioxidant capacity in the free radical 1,1-diphenyl-2-picrylhydrazyl tests.
  14. Ee GC, Teo SH, Kwong HC, Mohamed Tahir MI, Silong S
    PMID: 21589606 DOI: 10.1107/S1600536810048592
    The title compound, Artonol B, C(24)H(20)O(7), isolated from the stem bark of Artocarpus kemando, consists of four six-membered rings and one five-membered ring. The tricyclic xanthone ring system is almost planar [maximum deviation 0.115 (5) Å], whereas the pyran-oid ring is in a distorted boat conformation·The furan ring is almost coplanar with the fused aromatic ring, making a dihedral angle of 3.76 (9)°. The phenol ring serves as a intra-molecular hydrogen-bond donor to the adjacent carbonyl group and also acts as an inter-molecular hydrogen-bond acceptor for the methyl groups of adjacent mol-ecules, forming a three-dimensional network in the crystal.
  15. Tan GH, Taib NA, Choo WY, Teo SH, Yip CH
    Asian Pac J Cancer Prev, 2009 Jul-Sep;10(3):395-8.
    PMID: 19640180
    INTRODUCTION: Triple negative (TN) breast cancers are defined by a lack of expression of oestrogen, progesterone, and HER2 receptors. They tend to have a higher grade, with a poorer outcome compared to non-TN breast cancers.
    OBJECTIVE: The aim of this study is to determine the incidence of TN breast cancer in an Asian country consisting of Malays, Chinese and Indians, and to determine the factors associated with this type of breast cancer.
    RESULTS: The incidence of TN breast cancer in the University Malaya Medical Center is 17.6%. There is no significant difference amongst the Malays, Chinese and Indians. In bivariate analysis, TN breast cancer was significantly associated with younger age and Grade 3. However, in multivariate analysis using logistic regression, TN breast cancer was only associated with Grade 3.
    CONCLUSION: The incidence of TN breast cancer in our study is similar to other studies, and associated with a higher grade.
    Study site: University Malaya Medical Centre (UMMC)
  16. Kamal N, Sabaratnam V, Abdullah N, Ho AS, Teo SH, Lee HB
    Antonie Van Leeuwenhoek, 2009 Feb;95(2):179-88.
    PMID: 19125347 DOI: 10.1007/s10482-008-9301-8
    Photodynamic therapy (PDT) is a promising cancer treatment which involves activation of a photosensitizing drug with light to produce reactive oxygen species that kill tumors without causing damage to unirradiated normal tissues. To date, only Photofrin, Foscan and Levulan have been approved for clinical treatment of cancer. Tropical habitats such as those found in Malaysia are attractive sources of new therapeutic compounds as tremendous chemical diversity is found in a large number of plants, animals, marine- and micro-organisms. In our screening program for novel photosensitizers from nature, colorful strains of fungi (from Aspergillus and Penicillium genus) and bacteria (including actinomycetes and photosynthetic bacteria) were collected from various habitats in Peninsular Malaysia, such as coastal soil, peat soil, marine sponges and wastewater ponds. Methanolic extracts from a total of 85 different species were evaluated with a short-term cell viability assay for photo-cytotoxicity, where a promyelocytic leukemia cell-line, HL60 incubated with 20 microg/ml of extracts was irradiated with 9.6 J/cm(2) of a broad spectrum light. Two of these extracts, one from Rhodobacter sphaeroides (PBUM003) and one from Rhodopseudomonas palustris (PBUM001) showed moderate to strong photo-cytotoxicity. Subsequent bioassay guided isolation of the PBUM001 extract yielded known photosensitisers that are based on bacteriochlorophyll-a by comparing their molecular weight data, HPLC profiles and UV-vis absorption spectra with literature values, thereby demonstrating the validity of our screening approach.
  17. Lim KP, Hamid S, Lau SH, Teo SH, Cheong SC
    Oncol Rep, 2007 Jun;17(6):1321-6.
    PMID: 17487385 DOI: 10.3892/or.17.6.1321
    Inactivation of the retinoblastoma (pRB) pathway is a common event in oral squamous cell carcinoma particularly through the aberrant expression of the components within this pathway. This study examines the alterations of molecules within the pRB pathway by looking at the presence of homozygous deletions in p16(INK4A) and the expression patterns of pRB, cyclin D1 and CDK4, as well as the presence of human papillomavirus (HPV) in our samples. In our study, 5/20 samples demonstrated deletions of p16(INK4A) exon 1alpha. pRB overexpression was found in 20/20 samples, the expression was mainly observed in all layers of the epithelia, particularly in the basal layer where cells are actively dividing and aberrant pRB expression was found in 12/20 samples. Cyclin D1 and CDK4 overexpression was detected in 6/20 and 2/20 samples respectively in comparison to hyperplasias where both proteins were either not expressed or expressed at minimal levels (<10%). Strikingly, HPV was found to be present in all of our samples, suggesting that HPV plays a significant role in driving oral carcinogenesis. Notably, 17/20 of our samples showed more than one alteration in the pRB pathway, however, we did not find any significant relationship between the presence of HPV, homozygous deletion of p16(INK4A) and overexpression of pRB, cyclin D1 and CDK4. Collectively, this data demonstrates that alterations in the pRB pathway are a common event and involve the aberration of more than one molecule within the pathway. Furthermore, the involvement of HPV in all our samples suggests that HPV infection may play an important role in oral carcinogenesis.
  18. Lim KP, Sharifah H, Lau SH, Teo SH, Cheong SC
    Oncol Rep, 2005 Oct;14(4):963-8.
    PMID: 16142358 DOI: 10.3892/or.14.4.963
    The majority of global incidences of oral cancer occur in Asia, and the aetiology of oral cancer is different in Asia as it is in the West. However, whereas there is a growing understanding of the molecular mechanisms of oral cancer progression in the West, there is little progress in this understanding in Asia. In particular, the role of the p53 pathway in modulating cancer progression in Asian oral cancer remains unclear. In this study, we micro-dissected and analysed 20 well-differentiated oral squamous cell carcinoma specimens for alterations in the p53 pathway. We found that 6/20 samples contained mutations in the p53 gene which occurred in three hotspots, at codon 203, 218 and 296. Furthermore, 6/20 samples had a homozygous deletion of p14ARF, but notably p14ARF deletion and p53 mutation events were often independent and mutually exclusive. Strikingly, MDM2 was upregulated in 20/20 samples, but not in 3/3 normal tissue specimens. Taken together, these data suggest that inactivation of the p53 pathway is a frequent event in oral squamous cell carcinoma, which occurs by an aberration in one of a number of players in the p53 pathway.
  19. Hasmad HN, Sivanandan K, Lee V, Yip CH, Mohd Taib NA, Teo SH
    Clin Genet, 2015 Apr;87(4):392-4.
    PMID: 25066186 DOI: 10.1111/cge.12451
  20. Tan HY, Tan SL, Teo SH, Roebuck MM, Frostick SP, Kamarul T
    PeerJ, 2020;8:e8740.
    PMID: 32587790 DOI: 10.7717/peerj.8740
    Background: Type 2 diabetes mellitus (T2DM) had been reported to be associated with tendinopathy. However, the underlying mechanisms of diabetic tendinopathy still remain largely to be discovered. The purpose of this study was to develop insulin resistance (IR) model on primary human tenocytes (hTeno) culture with tumour necrosis factor-alpha (TNF-α) treatment to study tenocytes homeostasis as an implication for diabetic tendinopathy.

    Methods: hTenowere isolated from human hamstring tendon. Presence of insulin receptor beta (INSR-β) on normal tendon tissues and the hTeno monolayer culture were analyzed by immunofluorescence staining. The presence of Glucose Transporter Type 1 (GLUT1) and Glucose Transporter Type 4 (GLUT4) on the hTeno monolayer culture were also analyzed by immunofluorescence staining. Primary hTeno were treated with 0.008, 0.08, 0.8 and 8.0 µM of TNF-α, with and without insulin supplement. Outcome measures include 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino]-2-deoxy-d-glucose (2-NBDG) assay to determine the glucose uptake activity; colourimetric total collagen assay to quantify the total collagen expression levels; COL-I ELISA assay to measure the COL-I expression levels and real-time qPCR to analyze the mRNA gene expressions levels of Scleraxis (SCX), Mohawk (MKX), type I collagen (COL1A1), type III collagen (COL3A1), matrix metalloproteinases (MMP)-9 and MMP-13 in hTeno when treated with TNF-α. Apoptosis assay for hTeno induced with TNF-α was conducted using Annexin-V FITC flow cytometry analysis.

    Results: Immunofluorescence imaging showed the presence of INSR-β on the hTeno in the human Achilles tendon tissues and in the hTeno in monolayer culture. GLUT1 and GLUT4 were both positively expressed in the hTeno. TNF-α significantly reduced the insulin-mediated 2-NBDG uptake in all the tested concentrations, especially at 0.008 µM. Total collagen expression levels and COL-I expression levels in hTeno were also significantly reduced in hTeno treated with 0.008 µM of TNF-α. The SCX, MKX and COL1A1 mRNA expression levels were significantly downregulated in all TNF-α treated hTeno, whereas the COL3A1, MMP-9 and MMP-13 were significantly upregulated in the TNF-α treated cells. TNF-α progressively increased the apoptotic cells at 48 and 72 h.

    Conclusion: At 0.008 µM of TNF-α, an IR condition was induced in hTeno, supported with the significant reduction in glucose uptake, as well as significantly reduced total collagen, specifically COL-I expression levels, downregulation of candidate tenogenic markers genes (SCX and MKX), and upregulation of ECM catabolic genes (MMP-9 and MMP-13). Development of novel IR model in hTeno provides an insight on how tendon homeostasis could be affected and can be used as a tool for further discovering the effects on downstream molecular pathways, as the implication for diabetic tendinopathy.

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