Displaying publications 1 - 20 of 139 in total

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  1. Lim SH, Jahanshiri F, Jalilian FA, Rahim RA, Sekawi Z, Yusoff K
    Acta Virol., 2010;54(3):181-7.
    PMID: 20822310
    Human respiratory syncytial virus (HRSV) is a leading pathogen causing lower respiratory tract infections in infants and young children worldwide. In line with the development of an effective vaccine against HRSV, a domain of the fusion (F) glycoprotein of HRSV was produced and its immunogenicity and antigenic properties, namely the effect of deficient glycosylation was examined. A His-tagged recombinant F (rF) protein was expressed in Escherichia coli, solubilized with 8 mol/l urea, purified by the Ni-NTA affinity chromatography and used for the raising of a polyclonal antibody in rabbits. The non-glycosylated rF protein proved to be a strong immunogen that induced a polyclonal antibody that was able to recognize also the glycosylated F1 subunit of native HRSV. The other way around, a polyclonal antibody prepared against the native HRSV was able to react with the rF protein. These results indicated that glycosylation was not necessary for the F domain aa 212-574 in order to be recognized by the specific polyclonal antibody.
  2. Lim SH, Jahanshiri F, Rahim RA, Sekawi Z, Yusoff K
    Lett Appl Microbiol, 2010 Dec;51(6):658-64.
    PMID: 20973806 DOI: 10.1111/j.1472-765X.2010.02950.x
    A system for displaying heterologous respiratory syncytial virus (RSV) glycoproteins on the surface of Lactococcus lactis NZ9000 was developed.
  3. Yap PS, Lim SH, Hu CP, Yiap BC
    Phytomedicine, 2013 Jun 15;20(8-9):710-3.
    PMID: 23537749 DOI: 10.1016/j.phymed.2013.02.013
    In this study we investigated the relationship between several selected commercially available essential oils and beta-lactam antibiotics on their antibacterial effect against multidrug resistant bacteria. The antibacterial activity of essential oils and antibiotics was assessed using broth microdilution. The combined effects between essential oils of cinnamon bark, lavender, marjoram, tea tree, peppermint and ampicillin, piperacillin, cefazolin, cefuroxime, carbenicillin, ceftazidime, meropenem, were evaluated by means of the checkerboard method against beta-lactamase-producing Escherichia coli. In the latter assays, fractional inhibitory concentration (FIC) values were calculated to characterize interaction between the combinations. Substantial susceptibility of the bacteria toward natural antibiotics and a considerable reduction in the minimum inhibitory concentrations (MIC) of the antibiotics were noted in some paired combinations of antibiotics and essential oils. Out of 35 antibiotic-essential oil pairs tested, four of them showed synergistic effect (FIC≤0.5) and 31 pairs showed no interaction (FIC>0.5-4.0). The preliminary results obtained highlighted the occurrence of a pronounced synergistic relationship between piperacillin/cinnamon bark oil, piperacillin/lavender oil, piperacillin/peppermint oil as well as meropenem/peppermint oil against two of the three bacteria under study with a FIC index in the range 0.26-0.5. The finding highlighted the potential of peppermint, cinnamon bark and lavender essential oils being as antibiotic resistance modifying agent. Reduced usage of antibiotics could be employed as a treatment strategy to decrease the adverse effects and possibly to reverse the beta-lactam antibiotic resistance.
  4. Lim SH, Daghar L, Bullen C, Faiz HM, Akbar M, Amer Nordin AS, et al.
    Asia Pac J Public Health, 2020 11;32(8):414-417.
    PMID: 33084374 DOI: 10.1177/1010539520965370
    Previous studies documented the health disparities in smoking among sexual minority populations, including men who have sex with men (MSM). However, smoking behaviors have never been examined among Malaysian MSM, a sexual minority group in a predominantly Muslim country. A total of 622 Malaysian MSM completed an anonymous online survey in 2017. Data on the demographics, smoking and substance use behaviors, psychosocial factors, and attitudes toward smoking cessation were collected and analyzed. The mean age was 28 years and 67% of participants were of Malay ethnicity. The prevalence of current smoking was 23% (n = 143), while former smokers were 9% (n = 59). Current smoking status was associated with HIV-positive status and risk behaviors, such as suicidality, alcohol use, and illicit drug use (P = .001). Almost two thirds of current smokers had attempted to quit in the past year. Hence, comprehensive smoking cessation interventions addressing the psychosocial needs of MSM should be prioritized.
  5. Lim SH, Chin NL, Sulaiman A, Tay CH, Wong TH
    Foods, 2023 Jan 31;12(3).
    PMID: 36766121 DOI: 10.3390/foods12030592
    The safety, shelf life, and quality of fresh cow milk treated using industrial High-Pressure Processing (HPP) treatment at 600 MPa for 10 min was studied to identify the novelty of this non-thermal technology in milk processing. Changes in microbiological and physicochemical properties, including nutritional values of vitamins and amino acid profiles, were measured for a 60-day storage period at 6 °C +/- 1 °C. The HPP treatment produced milk that met all microbial safety requirements and exhibited a shelf life beyond 60 days in a hot and humid region. High physicochemical stability was achieved, with consistent pH and undetectable titratable acidity. The HPP treatment successfully retained all vitamins and minerals, including calcium (99.3%), phosphorus (99.4%), and magnesium (99.1%). However, the 60-day storage caused some degradation of Vitamin A (25%), B3 (91%), B5 (35%), B6 (80%), and C (85%), and minerals, including potassium (5%) and zinc (18%) when compared with fresh milk. This research has shown that the adoption of advanced treatment with HPP is very beneficial to the dairy industry in preserving milk quality in terms of its physicochemical and nutritional properties and extending its storage shelf life beyond 60 days.
  6. Lim SH, Alias H, Kien JKW, Akbar M, Kamarulzaman A, Wong LP
    AIDS Educ Prev, 2019 06;31(3):193-205.
    PMID: 31145000 DOI: 10.1521/aeap.2019.31.3.193
    This study aimed to examine the barriers and facilitators to HIV testing and treatment among Malaysian MSM. Between June 2014 and December 2015, in-depth interviews were conducted in 20 HIV-positive MSM recruited from a teaching hospital and NGO in Kuala Lumpur. Thematic analysis was used to identify, analyze, and report themes. Most participants investigated their HIV status after long period of sickness. Others sought testing upon partner's diagnosis and some were diagnosed via blood donation. Barriers to testing include personal (perceived good health, fear of positive result, denial); social and structural factors (stigmatization by health providers and family, lack of information about free HIV testing and long wait time). Barriers to treatment comprise personal factors (perceived HIV as incurable and treatment as complicated), social factors (HIV and homosexual stigma), and cost. Promoting benefits of regular testing and early treatment is needed to improve HIV care continuum among MSM in Malaysia.
  7. Lew SY, Teoh SL, Lim SH, Lim LW, Wong KH
    Mini Rev Med Chem, 2020;20(15):1518-1531.
    PMID: 32452327 DOI: 10.2174/1389557520666200526125534
    Depression is the most common form of mental illness and the major cause of disability worldwide. Symptoms of depression, including feelings of intense sadness and hopelessness, may occur after a specific event or in response to a gradual decline in health and functional status, often associated with aging. Current therapies for treating these symptoms include antidepressant drugs, counseling and behavioral therapy. However, antidepressant drugs are associated with mild to severe adverse effects, which has prompted the need for better treatment options. Medicinal mushrooms are valuable sources of food and medicine and are increasingly being used as supplements or as alternative medicines in standard healthcare. Numerous studies have provided insights into the neuroprotective effects of medicinal mushrooms, which are attributed to their antioxidant, anti-neuroinflammatory, cholinesterase inhibitory and neuroprotective properties. In this review, we comprehensively examine the role of these medicinal mushrooms in the treatment of depression. However, to apply these natural products in clinical settings, the therapeutic agent needs to be properly evaluated, including the active ingredients, the presence of synergistic effects, efficient extraction methods, and stabilization of the active ingredients for delivery into the body as well as crossing the blood-brain barrier.
  8. Subermaniam K, Yow YY, Lim SH, Koh OH, Wong KH
    Saudi J Biol Sci, 2020 Jun;27(6):1435-1445.
    PMID: 32489279 DOI: 10.1016/j.sjbs.2020.04.042
    Oxidative damage has been associated with the pathophysiology of depression. Macroalgae are equipped with antioxidant defense system to counteract the effects of free radicals. We explored the use of Malaysian Padina australis to attenuate high dose corticosterone-mediated oxidative damage in a cellular model mimicking depression. Fresh specimen of P. australis was freeze-dried and extracted sequentially with hexanes, ethyl acetate and ethanol. The extracts were screened for their phytochemical contents and antioxidant activities. Ethanol extract demonstrated the most potent antioxidant capacity and was selected for subsequent assays against high dose corticosterone of 600 µM-mediated oxidative damage in the rat pheochromocytoma (PC12) cells. The corticosterone reduced the cell viability, glutathione (GSH) level, aconitase activity, and mitochondrial membrane potential (MMP); and increased the lactate dehydrogenase (LDH) release, intracellular reactive oxygen species (ROS) level and apoptosis. However, the extent of oxidative damage was reversed by 0.25-0.5 mg/mL ethanol extract suggesting a possible role of P. australis-based antioxidants in the mitochondrial defense against constant ROS generation and regulation of antioxidant pathway. The effects were similar to that of desipramine, a tricyclic antidepressant. Our findings indicate that P. australis can be developed as a mitochondria-targeted antioxidant to mitigate antidepressant-like effects.
  9. Yow YY, Goh TK, Nyiew KY, Lim LW, Phang SM, Lim SH, et al.
    Cells, 2021 08 25;10(9).
    PMID: 34571842 DOI: 10.3390/cells10092194
    Despite the progressive advances, current standards of treatments for peripheral nerve injury do not guarantee complete recovery. Thus, alternative therapeutic interventions should be considered. Complementary and alternative medicines (CAMs) are widely explored for their therapeutic value, but their potential use in peripheral nerve regeneration is underappreciated. The present systematic review, designed according to guidelines of Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols, aims to present and discuss the current literature on the neuroregenerative potential of CAMs, focusing on plants or herbs, mushrooms, decoctions, and their respective natural products. The available literature on CAMs associated with peripheral nerve regeneration published up to 2020 were retrieved from PubMed, Scopus, and Web of Science. According to current literature, the neuroregenerative potential of Achyranthes bidentata, Astragalus membranaceus, Curcuma longa, Panax ginseng, and Hericium erinaceus are the most widely studied. Various CAMs enhanced proliferation and migration of Schwann cells in vitro, primarily through activation of MAPK pathway and FGF-2 signaling, respectively. Animal studies demonstrated the ability of CAMs to promote peripheral nerve regeneration and functional recovery, which are partially associated with modulations of neurotrophic factors, pro-inflammatory cytokines, and anti-apoptotic signaling. This systematic review provides evidence for the potential use of CAMs in the management of peripheral nerve injury.
  10. Subermaniam K, Lew SY, Yow YY, Lim SH, Yu WS, Lim LW, et al.
    Iran J Basic Med Sci, 2023;26(6):669-679.
    PMID: 37275754 DOI: 10.22038/IJBMS.2023.67835.14842
    OBJECTIVES: Neuroinflammation and microglial activation are pathological features in central nervous system disorders. Excess levels of reactive oxygen species (ROS) and pro-inflammatory cytokines have been implicated in exacerbation of neuronal damage during chronic activation of microglial cells. Padina australis, a brown macroalga, has been demonstrated to have various pharmacological properties such as anti-neuroinflammatory activity. However, the underlying mechanism mediating the anti-neuroinflammatory potential of P. australis remains poorly understood. We explored the use of Malaysian P. australis in attenuating lipopolysaccharide (LPS)-stimulated neuroinflammation in BV2 microglial cells.

    MATERIALS AND METHODS: Fresh specimens of P. australis were freeze-dried and subjected to ethanol extraction. The ethanol extract (PAEE) was evaluated for its protective effects against 1 µg/ml LPS-stimulated neuroinflammation in BV2 microglial cells.

    RESULTS: LPS reduced the viability of BV2 microglia cells and increased the levels of nitric oxide (NO), prostaglandin E2 (PGE2), intracellular reactive oxygen species (ROS), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6). However, the neuroinflammatory response was reversed by 0.5-2.0 mg/ml PAEE in a dose-dependent manner. Analysis of liquid chromatography-mass spectrometry (LC-MS) of PAEE subfractions revealed five compounds; methyl α-eleostearate, ethyl α-eleostearate, niacinamide, stearamide, and linoleic acid.

    CONCLUSION: The protective effects of PAEE against LPS-stimulated neuroinflammation in BV2 microglial cells were found to be mediated by the suppression of excess levels of intracellular ROS and pro-inflammatory mediators and cytokines, denoting the protective role of P. australis in combating continuous neuroinflammation. Our findings support the use of P. australis as a possible therapeutic for neuroinflammatory and neurodegenerative diseases.

  11. Lew SY, Lim SH, Lim LW, Wong KH
    BMC Complement Med Ther, 2020 Nov 11;20(1):340.
    PMID: 33176761 DOI: 10.1186/s12906-020-03132-x
    BACKGROUND: Hericium erinaceus is a culinary and medicinal mushroom in Traditional Chinese Medicines. It has numerous pharmacological effects including immunomodulatory, anti-tumour, anti-microbial, anti-aging and stimulation of nerve growth factor (NGF) synthesis, but little is known about its potential role in negating the detrimental effects of oxidative stress in depression. The present study investigated the neuroprotective effects of H. erinaceus standardised aqueous extract (HESAE) against high-dose corticosterone-induced oxidative stress in rat pheochromocytoma (PC-12) cells, a cellular model mimicking depression.

    METHODS: PC-12 cells was pre-treated with HESAE for 48 h followed by 400 μM corticosterone for 24 h to induce oxidative stress. Cells in complete medium without any treatment or pre-treated with 3.125 μg/mL desipramine served as the negative and positive controls, respectively. The cell viability, lactate dehydrogenase (LDH) release, endogenous antioxidant enzyme activities, aconitase activity, mitochondrial membrane potentials (MMPs), intracellular reactive oxygen species (ROS) levels and number of apoptotic nuclei were quantified. In addition, HESAE ethanol extract was separated into fractions by chromatographic methods prior to spectroscopic analysis.

    RESULTS: We observed that PC-12 cells treated with high-dose corticosterone at 400 μM had decreased cell viability, reduced endogenous antioxidant enzyme activities, disrupted mitochondrial function, and increased oxidative stress and apoptosis. However, pre-treatment with HESAE ranging from 0.25 to 1 mg/mL had increased cell viability, decreased LDH release, enhanced endogenous antioxidant enzyme activities, restored MMP, attenuated intracellular ROS and protected from ROS-mediated apoptosis. The neuroprotective effects could be attributed to significant amounts of adenosine and herierin III isolated from HESAE.

    CONCLUSIONS: HESAE demonstrated neuroprotective effects against high-dose corticosterone-induced oxidative stress in an in vitro model mimicking depression. HESAE could be a potential dietary supplement to treat depression.

  12. Wang M, Lim SH, Gibson BA, Azwa I, Guadamuz TE, Altice FL, et al.
    Int J STD AIDS, 2021 06;32(7):609-619.
    PMID: 33752518 DOI: 10.1177/0956462420970417
    Globally, cisgender women sex workers (CWSWs) and transgender women sex workers (TWSWs) experience increased vulnerabilities to HIV infection. Unfortunately, there is limited data on the drivers of HIV infection in these two understudied populations, particularly in Southeast Asia. To better understand factors associated with HIV infection, we evaluated correlates of newly diagnosed HIV infection in these two populations in Greater Kuala Lumpur, Malaysia. A total of 469 women (CWSW: n = 283; TWSW: n = 186) were included in this study. Most participants who tested HIV+ were unaware of their infection (59.6%; n = 34/57). Separate binary and multivariable logistic regressions were conducted to identify correlates of newly diagnosed HIV in CWSWs and TWSWs. Among CWSWs, Chlamydia trachomatis (aOR = 5.66; p = 0.007) and lifetime use of ecstasy/MDMA (aOR = 5.34; p = 0.03) were associated with newly diagnosed HIV, while condomless vaginal sex with clients was associated with lower likelihood of HIV infection (aOR = 0.98; p = 0.01). Among TWSWs, being single (aOR = 6.76; p = 0.03), using mobile application to solicit clients (aOR = 25.33; p = 0.006), and having C. trachomatis infection (aOR = 88.22, p = 0.02) were associated with newly diagnosed HIV. Expansion of HIV/sexually transmitted infection screening is needed to increase detection of HIV and linkage to care for sex workers. Interventions to reduce HIV infection among CWSWs and TWSWs should be tailored to these populations' unique vulnerabilities.
  13. Shrestha R, Galka JM, Azwa I, Lim SH, Guadamuz TE, Altice FL, et al.
    Transgend Health, 2020;5(3):182-190.
    PMID: 32923668 DOI: 10.1089/trgh.2019.0085
    Background: While global research on the implementation of HIV self-testing (HIVST) has increased exponentially, few studies have assessed information on HIVST uptake factors (i.e., willingness, preferences) in transgender women (TW) and none in the Malaysian context. We therefore sought to assess willingness to use HIVST among this understudied key population. Methods: A cross-sectional survey was conducted among 361 HIV-negative Malaysian TW in 2017. Participants were recruited using flyers, announcements through social media, and direct referral from staff members of the community-based organizations serving the TW communities. Multivariable logistic regression was used to identify correlates of willingness to use HIVST. Results: Nearly half of the participants (47.6%) reported that they would be willing to use HIVST. Multivariable analysis showed that willingness to use HIVST was positively associated with having experienced sexual assault in childhood (adjusted odds ratio [aOR]=3.239, p<0.001), having ever used mobile phone or apps to find sex work clients (aOR=1.677, p=0.040), and having engaged in condomless sex in the past 6 months (aOR=1.886, p=0.018). In contrast, living in Kuala Lumpur (aOR=0.559, p=0.032), having higher number of sex work clients per day (aOR=0.927, p=0.004), and current depressive symptoms (aOR=0.576, p=0.026) were negatively associated with willingness to use HIVST. Conclusions: Findings in this study suggest that TW in our sample were moderately willing to use HIVST. Especially important here is the increased interest in HIVST among TW who are at higher risk for HIV infection. Overall, our findings underscore the need for additional research on how to most effectively implement HIVST for key populations, including TW, such that uptake and retention in regular HIV screening is sustained.
  14. Galka JM, Wang M, Azwa I, Gibson B, Lim SH, Shrestha R, et al.
    Transgend Health, 2020 Dec;5(4):258-266.
    PMID: 33644315 DOI: 10.1089/trgh.2020.0003
    Introduction: Transgender women (TW) face one of the highest HIV burdens worldwide. In Malaysia, 12.4% of TW are HIV infected, ∼30-fold higher than in the Malaysian adult population. Pre-exposure prophylaxis (PrEP) is a highly effective HIV prevention strategy, however, little is known about TW's willingness to use PrEP or their preferences for receiving PrEP. This study examined the correlates of Malaysian TW's willingness to use PrEP and their attitudes and preferences related to delivery of PrEP and PrEP-related care. Methods: Between June and August 2017, 361 TW in Malaysia completed an online survey about their knowledge of and willingness to use PrEP for HIV prevention. Results: Only 20.2% of participants had ever previously heard of PrEP and none were currently taking PrEP. The majority (82.5%) expressed high willingness to take PrEP and most participants met the World Health Organization (WHO) indication for PrEP (82.3%). In the multivariate model, lifetime hormone use, prior postexposure prophylaxis use, and having completed a high school education were associated with higher willingness to use PrEP, while injection drug use, older age, and Chinese ethnicity were associated with lower PrEP willingness. Conclusion: TW in Malaysia are highly willing to use PrEP for HIV prevention. Differences in willingness to use PrEP identified by education, ethnicity, substance abuse, and age suggest different strategies may be needed to scale-up PrEP for this diverse community of TW.
  15. Jin H, Friedman MR, Lim SH, Guadamuz TE, Wei C
    LGBT Health, 2016 Dec;3(6):465-471.
    PMID: 26982598
    PURPOSE: Men who have sex with men and are sex workers (MSMSW) are disproportionately affected by the growing and emerging HIV epidemic. As sex work and same-sex behavior are heavily stigmatized and often illegal in most Asian countries, HIV research focusing on MSMSW has been limited. The goal of this analysis is to examine HIV testing practices and identify correlates of HIV testing among MSMSW in Asia.

    METHODS: The Asia Internet MSM Sex Survey, an online cross-sectional survey of 10,861 men who have sex with men (MSM), was conducted in 2010. Data on sociodemographic characteristics, HIV testing behaviors, and sexual behaviors were collected. Five hundred and seventy-four HIV-negative/unknown respondents reported receiving payment for sex with men at least once in the past 6 months and were included in this analysis. Multivariable logistic regression was conducted to identify independent correlates of HIV testing in the past year.

    RESULTS: About half (48.6%) of the participants had been tested for HIV at least once within the past year, and 30.5% had never been tested. We also found that MSMSW participants who engaged in risky behaviors were less likely to be tested.

    CONCLUSION: While one might expect a high HIV testing rate among MSMSW due to the risks associated with engaging in sex work, we found that HIV testing uptake is suboptimal among MSMSW in Asia. These results suggest that targeted HIV prevention and testing promotion among MSMSW are needed.

  16. Yang C, Guadamuz TE, Lim SH, Koe S, Wei C
    LGBT Health, 2016 Apr;3(2):168-74.
    PMID: 26789393 DOI: 10.1089/lgbt.2014.0041
    We explored factors associated with alcohol use before or during sex among a sample of 10,861 men who have sex with men (MSM) in Asia who were recruited online for the study. Multinomial logistic regression analysis indicated that having sex under the influence of alcohol was associated with having multiple male partners, seeking partners primarily through gay bar/gym/dance party/friends, selling sex and using multiple drugs during the past 6 months, and unprotected anal sex. More efforts are needed to better assess alcohol use and misuse among MSM in Asia and understand contextual influences on alcohol use and HIV-related behaviors in order to implement culturally-specific interventions.
  17. Chong SL, Mou DG, Ali AM, Lim SH, Tey BT
    Hybridoma (Larchmt), 2008 Apr;27(2):107-11.
    PMID: 18642675
    The effect of mild hypothermic (32 degrees C) conditions on cell growth, cell-cycle progress, and antibody production of hybridoma C2E7 cells was investigated in the present study. The growth of hybridoma cells was slower during the mild hypothermic condition compared to that at 37 degrees C; this led to about 10% decrease in maximum viable cell density and volumetric antibody productivity. However, under mild hypothermic growth conditions, the culture viability was substantially improved and the specific antibody productivity was enhanced compared to that at 37 degrees C. The average specific productivity for the entire batch culture at 32 degrees C is about 5% higher than that at 37 degrees C. Cell-cycle analysis data showed that there was no growth arrestment during the mild hypothermic growth of hybridoma cells. The G1-phase cells were increased, while the S-phase cells were decreased gradually as the culture time progressed. Further analysis showed that the specific antibody productivity of hybridoma cells was correlated to the fraction of S-phase cells.
  18. Ho WK, Tai MC, Dennis J, Shu X, Li J, Ho PJ, et al.
    Genet Med, 2022 Mar;24(3):586-600.
    PMID: 34906514 DOI: 10.1016/j.gim.2021.11.008
    PURPOSE: Non-European populations are under-represented in genetics studies, hindering clinical implementation of breast cancer polygenic risk scores (PRSs). We aimed to develop PRSs using the largest available studies of Asian ancestry and to assess the transferability of PRS across ethnic subgroups.

    METHODS: The development data set comprised 138,309 women from 17 case-control studies. PRSs were generated using a clumping and thresholding method, lasso penalized regression, an Empirical Bayes approach, a Bayesian polygenic prediction approach, or linear combinations of multiple PRSs. These PRSs were evaluated in 89,898 women from 3 prospective studies (1592 incident cases).

    RESULTS: The best performing PRS (genome-wide set of single-nucleotide variations [formerly single-nucleotide polymorphism]) had a hazard ratio per unit SD of 1.62 (95% CI = 1.46-1.80) and an area under the receiver operating curve of 0.635 (95% CI = 0.622-0.649). Combined Asian and European PRSs (333 single-nucleotide variations) had a hazard ratio per SD of 1.53 (95% CI = 1.37-1.71) and an area under the receiver operating curve of 0.621 (95% CI = 0.608-0.635). The distribution of the latter PRS was different across ethnic subgroups, confirming the importance of population-specific calibration for valid estimation of breast cancer risk.

    CONCLUSION: PRSs developed in this study, from association data from multiple ancestries, can enhance risk stratification for women of Asian ancestry.

  19. Ang BH, Ho WK, Wijaya E, Kwan PY, Ng PS, Yoon SY, et al.
    J Clin Oncol, 2022 May 10;40(14):1542-1551.
    PMID: 35143328 DOI: 10.1200/JCO.21.01647
    PURPOSE: With the development of poly (ADP-ribose) polymerase inhibitors for treatment of patients with cancer with an altered BRCA1 or BRCA2 gene, there is an urgent need to ensure that there are appropriate strategies for identifying mutation carriers while balancing the increased demand for and cost of cancer genetics services. To date, the majority of mutation prediction tools have been developed in women of European descent where the age and cancer-subtype distributions are different from that in Asian women.

    METHODS: In this study, we built a new model (Asian Risk Calculator) for estimating the likelihood of carrying a pathogenic variant in BRCA1 or BRCA2 gene, using germline BRCA genetic testing results in a cross-sectional population-based study of 8,162 Asian patients with breast cancer. We compared the model performance to existing mutation prediction models. The models were evaluated for discrimination and calibration.

    RESULTS: Asian Risk Calculator included age of diagnosis, ethnicity, bilateral breast cancer, tumor biomarkers, and family history of breast cancer or ovarian cancer as predictors. The inclusion of tumor grade improved significantly the model performance. The full model was calibrated (Hosmer-Lemeshow P value = .614) and discriminated well between BRCA and non-BRCA pathogenic variant carriers (area under receiver operating curve, 0.80; 95% CI, 0.75 to 0.84). Addition of grade to the existing clinical genetic testing criteria targeting patients with breast cancer age younger than 45 years reduced the proportion of patients referred for genetic counseling and testing from 37% to 33% (P value = .003), thereby improving the overall efficacy.

    CONCLUSION: Population-specific customization of mutation prediction models and clinical genetic testing criteria improved the accuracy of BRCA mutation prediction in Asian patients.

  20. Ng KT, Ong LY, Lim SH, Takebe Y, Kamarulzaman A, Tee KK
    PLoS One, 2013;8(6):e67286.
    PMID: 23840653 DOI: 10.1371/journal.pone.0067286
    HIV-1 epidemics among men who have sex with men (MSM) continue to expand in developed and developing countries. Although HIV infection in MSM is amongst the highest of the key affected populations in many countries in Southeast Asia, comprehensive molecular epidemiological study of HIV-1 among MSM remains inadequate in the region including in Malaysia. Here, we reported the phylodynamic profiles of HIV-1 genotypes circulating among MSM population in Kuala Lumpur, Malaysia. A total of n = 459 newly-diagnosed treatment-naïve consenting subjects were recruited between March 2006 and August 2012, of whom 87 (18.9%) were self-reported MSM. Transmitted drug resistance mutations were absent in these isolates. Cumulatively, phylogenetic reconstructions of the pro-rt gene (HXB2∶2253-3275) showed that HIV-1 subtype B and CRF01_AE were predominant and contributed to approximately 80% of the total HIV-1 infection among MSM. In addition to numerous unique transmission lineages within these genotypes, twelve monophyletic transmission clusters of different sizes (2-7 MSM sequences, supported by posterior probability value of 1) were identified in Malaysia. Bayesian coalescent analysis estimated that the divergence times for these clusters were mainly dated between 1995 and 2005 with four major transmission clusters radiating at least 12 years ago suggesting that active spread of multiple sub-epidemic clusters occurred during this period. The changes in effective population size of subtype B showed an exponential growth within 5 years between 1988 and 1993, while CRF01_AE lineage exhibited similar expansion between 1993 and 2003. Our study provides the first insight of the phylodynamic profile of HIV-1 subtype B and CRF01_AE circulating among MSM population in Kuala Lumpur, Malaysia, unravelling the importance of understanding transmission behaviours as well as evolutionary history of HIV-1 in assessing the risk of outbreak or epidemic expansion.
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