Displaying publications 61 - 80 of 211 in total

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  1. Jong WW, Tan PJ, Kamarulzaman FA, Mejin M, Lim D, Ang I, et al.
    Chem Biodivers, 2013 Aug;10(8):1475-86.
    PMID: 23939795 DOI: 10.1002/cbdv.201200303
    Photodynamic therapy (PDT) is a medical treatment that involves the irradiation of an administered photosensitizing drug with light of a particular wavelength to activate the photosensitizer to kill abnormal cells. To date, only a small number of photosensitizers have been clinically approved for PDT, and researchers continue to look for new molecules that have more desirable properties for clinical applications. Natural products have long been important sources of pharmaceuticals, and there is a great potential for discovery of novel chemotypes from under-explored biodiversities in the world. The objective of this study is to mine the terrestrial plants in Sarawak, Borneo Island, for new photosensitizers for PDT. In a screening program from 2004 to 2008, we prepared and studied 2,400 extracts from 888 plants for their photosensitizing activities. This report details the bioprospecting process, preparation and testing of extracts, analysis of the active samples, fractionation of four samples, and isolation and characterization of photosensitizers.
  2. Kamarulzaman FA, Shaari K, Ho AS, Lajis NH, Teo SH, Lee HB
    Chem Biodivers, 2011 Mar;8(3):494-502.
    PMID: 21404433 DOI: 10.1002/cbdv.201000341
    In our screening program for new photosensitizers from Malaysian biodiversity for photodynamic therapy (PDT) of cancer, MeOH extracts of ten terrestrial plants from Cameron Highlands in Pahang, Peninsular Malaysia, were tested. In a short-term 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, 20 μg/ml each of these extracts were incubated in a pro-myelocytic leukemia cell-line, HL60, with or without irradiation with 9.6 J/cm(2) of a broad spectrum light. Three samples, Labisia longistyla, Dichroa febrifuga, and Piper penangense, were photocytotoxic by having at least twofold lower cell viability when irradiated compared to the unirradiated assay. The extract of the leaves of Piper penangense, a shrub belonging to the family Piperaceae and widely distributed in the tropical and subtropical regions in the world, was subsequently subjected to bioassay-guided fractionation using standard chromatography methods. Eight derivatives of pheophorbide-a and -b were identified from the fractions that exhibited strong photocytotoxicity. By spectroscopic analysis, these compounds were identified as pheophorbide-a methyl ester (1), (R,S)-13(2) -hydroxypheophorbide-a methyl ester (2 and 3), pheophorbide-b methyl ester (4), 13(2) -hydroxypheophorbide-b methyl ester (5), 15(2) -hydroxylactone pheophorbide-a methyl ester (6), 15(2) -methoxylactone pheophorbide-a methyl ester (7), 15(2) -methoxylactone pheophorbide-b methyl ester (8).
  3. 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.
  4. 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.
  5. 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
  6. 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.
  7. Hakkaart C, Pearson JF, Marquart L, Dennis J, Wiggins GAR, Barnes DR, et al.
    Commun Biol, 2022 Oct 06;5(1):1061.
    PMID: 36203093 DOI: 10.1038/s42003-022-03978-6
    The contribution of germline copy number variants (CNVs) to risk of developing cancer in individuals with pathogenic BRCA1 or BRCA2 variants remains relatively unknown. We conducted the largest genome-wide analysis of CNVs in 15,342 BRCA1 and 10,740 BRCA2 pathogenic variant carriers. We used these results to prioritise a candidate breast cancer risk-modifier gene for laboratory analysis and biological validation. Notably, the HR for deletions in BRCA1 suggested an elevated breast cancer risk estimate (hazard ratio (HR) = 1.21), 95% confidence interval (95% CI = 1.09-1.35) compared with non-CNV pathogenic variants. In contrast, deletions overlapping SULT1A1 suggested a decreased breast cancer risk (HR = 0.73, 95% CI 0.59-0.91) in BRCA1 pathogenic variant carriers. Functional analyses of SULT1A1 showed that reduced mRNA expression in pathogenic BRCA1 variant cells was associated with reduced cellular proliferation and reduced DNA damage after treatment with DNA damaging agents. These data provide evidence that deleterious variants in BRCA1 plus SULT1A1 deletions contribute to variable breast cancer risk in BRCA1 carriers.
  8. Zulkhernain NS, Teo SH, Patel V, Tan PJ
    Curr Cancer Drug Targets, 2014;14(8):764-73.
    PMID: 25348017 DOI: 10.2174/1568009614666141028121347
    Targeted therapy, the treatment of cancer based on an underlying genetic alteration, is rapidly gaining favor as the preferred therapeutic approach. To date, although natural products represent a rich resource of bio-diverse drug candidates, only a few have been identified to be effective as targeted cancer therapies largely due to the incompatibilities to current high-throughput screening methods. In this article, we review the utility of a zebrafish developmental screen for bioactive natural product-based compounds that target signaling pathways that are intimately shared with those in humans. Any bioactive compound perturbing signaling pathways identified from phenotypic developmental defects in zebrafish embryos provide an opportunity for developing targeted therapies for human cancers. This model provides a promising tool in the search for targeted cancer therapeutics from natural products.
  9. Chai SJ, Ahmad Zabidi MM, Gan SP, Rajadurai P, Lim PVH, Ng CC, et al.
    Dis Markers, 2019;2019:3857853.
    PMID: 31236144 DOI: 10.1155/2019/3857853
    Nasopharyngeal carcinoma (NPC) is a highly metastatic cancer prevalent in Southern China and Southeast Asia. The current knowledge on the molecular pathogenesis of NPC is still inadequate to improve disease management. Using gene expression microarrays, we have identified the four-jointed box 1 (FJX1) gene to be upregulated in primary NPC tissues relative to nonmalignant tissues. An orthologue of human FJX1, the four-jointed (fj) gene in Drosophila and Fjx1 in mouse, has reported to be associated with cancer progression pathways. However, the exact function of FJX1 in human is not well characterized. The overexpression of FJX1 mRNA was validated in primary NPC tissue samples, and the level of FJX1 protein was significantly higher in a subset of NPC tissues (42%) compared to the normal epithelium, where no expression of FJX1 was observed (p = 0.01). FJX1 is also found to be overexpressed in microarray datasets and TCGA datasets of other cancers including head and neck cancer, colorectal, and ovarian cancer. Both siRNA knockdown and overexpression experiments in NPC cell lines showed that FJX1 promotes cell proliferation, anchorage-dependent growth, and cellular invasion. Cyclin D1 and E1 mRNA levels were increased following FJX1 expression indicating that FJX1 enhances proliferation by regulating key proteins governing the cell cycle. Our data suggest that the overexpression of FJX1 contributes to a more aggressive phenotype of NPC cells and further investigations into FJX1 as a potential therapeutic target for NPC are warranted. The evaluation of FJX1 as an immunotherapy target for NPC and other cancers is currently ongoing.
  10. Yang Y, Shu X, Shu XO, Bolla MK, Kweon SS, Cai Q, et al.
    EBioMedicine, 2019 Oct;48:203-211.
    PMID: 31629678 DOI: 10.1016/j.ebiom.2019.09.006
    BACKGROUND: We previously conducted a systematic field synopsis of 1059 breast cancer candidate gene studies and investigated 279 genetic variants, 51 of which showed associations. The major limitation of this work was the small sample size, even pooling data from all 1059 studies. Thereafter, genome-wide association studies (GWAS) have accumulated data for hundreds of thousands of subjects. It's necessary to re-evaluate these variants in large GWAS datasets.

    METHODS: Of these 279 variants, data were obtained for 228 from GWAS conducted within the Asian Breast Cancer Consortium (24,206 cases and 24,775 controls) and the Breast Cancer Association Consortium (122,977 cases and 105,974 controls of European ancestry). Meta-analyses were conducted to combine the results from these two datasets.

    FINDINGS: Of those 228 variants, an association was observed for 12 variants in 10 genes at a Bonferroni-corrected threshold of P 

  11. Song CV, Teo SH, Taib NA, Yip CH
    Ecancermedicalscience, 2018;12:863.
    PMID: 30174725 DOI: 10.3332/ecancer.2018.863
    Introduction: The presence of a deleterious mutation, most commonly a BRCA mutation, has a tremendous impact on the management of breast cancer. We review the surgical management of BRCA mutation carriers, and two other potentially high-risk mutations, TP53 and PALB2.

    Methodology: A search was done on PubMed, limited to reviews and the English language only. The search terms used were 'BRCA' or 'PALB2' or 'TP53' and 'surgery'. Fifteen articles were identified by searching and one article was obtained from other sources.

    Results: Breast-conserving surgery has equivalent survival, but may have an increased risk of local recurrence, compared to mastectomy among BRCA mutation carriers. Contralateral prophylactic mastectomy may not improve overall survival, despite reducing the risk of developing contralateral breast cancer. The use of preoperative genetic testing allows patients to have combined curative and prophylactic surgery. However, preoperative genetic testing may influence patients to make rash decisions. In healthy BRCA mutation carriers, bilateral prophylactic mastectomy is done to prevent breast cancer from occurring. Bilateral prophylactic mastectomy is highly effective in reducing the risk of breast cancer in healthy BRCA mutation-positive women and may have a survival benefit. Prophylactic oophorectomy reduces the risk of ovarian cancer, but may not have an effect on the risk of breast cancer. There is a lack of studies on surgery for non-BRCA mutations. TP53 and PALB2 are potentially high-risk mutations for breast cancer, which may justify the use of prophylactic surgery. Advice should be given on a case-by-case basis.

    Conclusion: A comprehensive approach is needed to provide optimum treatment for breast cancer patients with deleterious mutations.

  12. Shamsuddin MR, Teo SH, Azmi TSMT, Lahuri AH, Taufiq-Yap YH
    PMID: 38635095 DOI: 10.1007/s11356-024-33325-7
    Alkali sludge (AS) is waste abundantly generated from solar photovoltaic (PV) solar cell industries. Since this potential basic material is still underutilized, a combination with NiO catalyst might greatly influence coke resentence, especially in high-temperature thermochemical reactions (Arora and Prasad, RSC Adv. 6:108,668-108688, 2016). This paper investigated alkaline sludge containing 3CaO-2SiO2 doped with well-known NiO to enhance the dry reforming of methane (DRM) reaction. The wet-impregnation method was used to prepare the xNiO/AS (x = 5-15%) catalysts. Subsequently, all catalysts were tested by using X-ray diffraction (XRD), nitrogen adsorption/desorption (BET), temperature-programmed reduction of hydrogen (H2-TPR), temperature-programmed desorption of carbon dioxide (TPD-CO2), field emission scanning electron microscopy (FESEM-EDX), and X-ray photoelectron spectroscopy (XPS). The spent catalysts were analyzed by thermogravimetric analysis (TGA/DTG), transmission electron microscopy (TEM), and temperature-programmed oxidation (TPO). The catalytic performance of xNiO/AS catalysts was investigated in a fixed bed reactor connected with gas chromatography thermal conductivity detector (GC-TCD) at a CH4:CO2 flow rate of 30 mL-1 during a 10-h reaction by following (Shamsuddin et al., Int. J. Energy Res. 45:15,463-15,480, 2021d). For optimization parameters, the effects of NiO concentration (5, 10, and 15%), reaction temperature (700, 750, 800, 850, and 900 °C), catalyst loading (0.1, 0.2, 0.3, 0.4, and 0.5 g), and gas hourly space velocity (GHSV) range from 3000, 6000, 9000, 12,000, and 15,000 h-1 were evaluated. The results showed that physical characteristics such as BET surface area and porosity do not significantly impact NiO percentages of dispersion, whereas chemical characteristics like reducibility are crucial for the catalysts' efficient catalytic activity. Due to the active sites on the catalyst surface being more accessible, increased NiO dispersion resulted in higher reactant conversion. The catalytic performance on various parameters that showed 15%NiO/AS exhibited high reactant conversion up to 98% and 40-60% product selectivity in 700 °C, 0.2 g catalyst loading, and 12,000 h-1 GHSV. According to spent catalyst analyses, the catalyst was stable even after the DRM reaction. Meanwhile, increased reducibility resulted in more and better active site formation on the catalyst. Synergetic effect of efficient NiO as active metal and medium basic sites from AS enhanced DRM catalytic activity and stability with low coke formation.
  13. Grootes I, Keeman R, Blows FM, Milne RL, Giles GG, Swerdlow AJ, et al.
    Eur J Cancer, 2022 Sep;173:178-193.
    PMID: 35933885 DOI: 10.1016/j.ejca.2022.06.011
    BACKGROUND: Predict Breast (www.predict.nhs.uk) is an online prognostication and treatment benefit tool for early invasive breast cancer. The aim of this study was to incorporate the prognostic effect of progesterone receptor (PR) status into a new version of PREDICT and to compare its performance to the current version (2.2).

    METHOD: The prognostic effect of PR status was based on the analysis of data from 45,088 European patients with breast cancer from 49 studies in the Breast Cancer Association Consortium. Cox proportional hazard models were used to estimate the hazard ratio for PR status. Data from a New Zealand study of 11,365 patients with early invasive breast cancer were used for external validation. Model calibration and discrimination were used to test the model performance.

    RESULTS: Having a PR-positive tumour was associated with a 23% and 28% lower risk of dying from breast cancer for women with oestrogen receptor (ER)-negative and ER-positive breast cancer, respectively. The area under the ROC curve increased with the addition of PR status from 0.807 to 0.809 for patients with ER-negative tumours (p = 0.023) and from 0.898 to 0.902 for patients with ER-positive tumours (p = 2.3 × 10-6) in the New Zealand cohort. Model calibration was modest with 940 observed deaths compared to 1151 predicted.

    CONCLUSION: The inclusion of the prognostic effect of PR status to PREDICT Breast has led to an improvement of model performance and more accurate absolute treatment benefit predictions for individual patients. Further studies should determine whether the baseline hazard function requires recalibration.

  14. Laitman Y, Feng BJ, Zamir IM, Weitzel JN, Duncan P, Port D, et al.
    Eur J Hum Genet, 2013 Feb;21(2):212-6.
    PMID: 22763381 DOI: 10.1038/ejhg.2012.124
    The 185delAG* BRCA1 mutation is encountered primarily in Jewish Ashkenazi and Iraqi individuals, and sporadically in non-Jews. Previous studies estimated that this is a founder mutation in Jewish mutation carriers that arose before the dispersion of Jews in the Diaspora ~2500 years ago. The aim of this study was to assess the haplotype in ethnically diverse 185delAG* BRCA1 mutation carriers, and to estimate the age at which the mutation arose. Ethnically diverse Jewish and non-Jewish 185delAG*BRCA1 mutation carriers and their relatives were genotyped using 15 microsatellite markers and three SNPs spanning 12.5 MB, encompassing the BRCA1 gene locus. Estimation of mutation age was based on a subset of 11 markers spanning a region of ~5 MB, using a previously developed algorithm applying the maximum likelihood method. Overall, 188 participants (154 carriers and 34 noncarriers) from 115 families were included: Ashkenazi, Iraq, Kuchin-Indians, Syria, Turkey, Iran, Tunisia, Bulgaria, non-Jewish English, non-Jewish Malaysian, and Hispanics. Haplotype analysis indicated that the 185delAG mutation arose 750-1500 years ago. In Ashkenazim, it is a founder mutation that arose 61 generations ago, and with a small group of founder mutations was introduced into the Hispanic population (conversos) ~650 years ago, and into the Iraqi-Jewish community ~450 years ago. The 185delAG mutation in the non-Jewish populations in Malaysia and the UK arose at least twice independently. We conclude that the 185delAG* BRCA1 mutation resides on a common haplotype among Ashkenazi Jews, and arose about 61 generations ago and arose independently at least twice in non-Jews.
  15. Dareng EO, Tyrer JP, Barnes DR, Jones MR, Yang X, Aben KKH, et al.
    Eur J Hum Genet, 2022 Jan 14.
    PMID: 35027648 DOI: 10.1038/s41431-021-00987-7
    Polygenic risk scores (PRS) for epithelial ovarian cancer (EOC) have the potential to improve risk stratification. Joint estimation of Single Nucleotide Polymorphism (SNP) effects in models could improve predictive performance over standard approaches of PRS construction. Here, we implemented computationally efficient, penalized, logistic regression models (lasso, elastic net, stepwise) to individual level genotype data and a Bayesian framework with continuous shrinkage, "select and shrink for summary statistics" (S4), to summary level data for epithelial non-mucinous ovarian cancer risk prediction. We developed the models in a dataset consisting of 23,564 non-mucinous EOC cases and 40,138 controls participating in the Ovarian Cancer Association Consortium (OCAC) and validated the best models in three populations of different ancestries: prospective data from 198,101 women of European ancestries; 7,669 women of East Asian ancestries; 1,072 women of African ancestries, and in 18,915 BRCA1 and 12,337 BRCA2 pathogenic variant carriers of European ancestries. In the external validation data, the model with the strongest association for non-mucinous EOC risk derived from the OCAC model development data was the S4 model (27,240 SNPs) with odds ratios (OR) of 1.38 (95% CI: 1.28-1.48, AUC: 0.588) per unit standard deviation, in women of European ancestries; 1.14 (95% CI: 1.08-1.19, AUC: 0.538) in women of East Asian ancestries; 1.38 (95% CI: 1.21-1.58, AUC: 0.593) in women of African ancestries; hazard ratios of 1.36 (95% CI: 1.29-1.43, AUC: 0.592) in BRCA1 pathogenic variant carriers and 1.49 (95% CI: 1.35-1.64, AUC: 0.624) in BRCA2 pathogenic variant carriers. Incorporation of the S4 PRS in risk prediction models for ovarian cancer may have clinical utility in ovarian cancer prevention programs.
  16. Dareng EO, Tyrer JP, Barnes DR, Jones MR, Yang X, Aben KKH, et al.
    Eur J Hum Genet, 2022 May;30(5):630-631.
    PMID: 35314806 DOI: 10.1038/s41431-022-01085-y
  17. Bancroft EK, Page EC, Castro E, Lilja H, Vickers A, Sjoberg D, et al.
    Eur Urol, 2014 Sep;66(3):489-99.
    PMID: 24484606 DOI: 10.1016/j.eururo.2014.01.003
    BACKGROUND: Men with germline breast cancer 1, early onset (BRCA1) or breast cancer 2, early onset (BRCA2) gene mutations have a higher risk of developing prostate cancer (PCa) than noncarriers. IMPACT (Identification of Men with a genetic predisposition to ProstAte Cancer: Targeted screening in BRCA1/2 mutation carriers and controls) is an international consortium of 62 centres in 20 countries evaluating the use of targeted PCa screening in men with BRCA1/2 mutations.

    OBJECTIVE: To report the first year's screening results for all men at enrollment in the study.

    DESIGN, SETTING AND PARTICIPANTS: We recruited men aged 40-69 yr with germline BRCA1/2 mutations and a control group of men who have tested negative for a pathogenic BRCA1 or BRCA2 mutation known to be present in their families. All men underwent prostate-specific antigen (PSA) testing at enrollment, and those men with PSA >3 ng/ml were offered prostate biopsy.

    OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: PSA levels, PCa incidence, and tumour characteristics were evaluated. The Fisher exact test was used to compare the number of PCa cases among groups and the differences among disease types.

    RESULTS AND LIMITATIONS: We recruited 2481 men (791 BRCA1 carriers, 531 BRCA1 controls; 731 BRCA2 carriers, 428 BRCA2 controls). A total of 199 men (8%) presented with PSA >3.0 ng/ml, 162 biopsies were performed, and 59 PCas were diagnosed (18 BRCA1 carriers, 10 BRCA1 controls; 24 BRCA2 carriers, 7 BRCA2 controls); 66% of the tumours were classified as intermediate- or high-risk disease. The positive predictive value (PPV) for biopsy using a PSA threshold of 3.0 ng/ml in BRCA2 mutation carriers was 48%-double the PPV reported in population screening studies. A significant difference in detecting intermediate- or high-risk disease was observed in BRCA2 carriers. Ninety-five percent of the men were white, thus the results cannot be generalised to all ethnic groups.

    CONCLUSIONS: The IMPACT screening network will be useful for targeted PCa screening studies in men with germline genetic risk variants as they are discovered. These preliminary results support the use of targeted PSA screening based on BRCA genotype and show that this screening yields a high proportion of aggressive disease.

    PATIENT SUMMARY: In this report, we demonstrate that germline genetic markers can be used to identify men at higher risk of prostate cancer. Targeting screening at these men resulted in the identification of tumours that were more likely to require treatment.

  18. Page EC, Bancroft EK, Brook MN, Assel M, Hassan Al Battat M, Thomas S, et al.
    Eur Urol, 2019 Dec;76(6):831-842.
    PMID: 31537406 DOI: 10.1016/j.eururo.2019.08.019
    BACKGROUND: Mutations in BRCA2 cause a higher risk of early-onset aggressive prostate cancer (PrCa). The IMPACT study is evaluating targeted PrCa screening using prostate-specific-antigen (PSA) in men with germline BRCA1/2 mutations.

    OBJECTIVE: To report the utility of PSA screening, PrCa incidence, positive predictive value of PSA, biopsy, and tumour characteristics after 3 yr of screening, by BRCA status.

    DESIGN, SETTING, AND PARTICIPANTS: Men aged 40-69 yr with a germline pathogenic BRCA1/2 mutation and male controls testing negative for a familial BRCA1/2 mutation were recruited. Participants underwent PSA screening for 3 yr, and if PSA > 3.0 ng/ml, men were offered prostate biopsy.

    OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: PSA levels, PrCa incidence, and tumour characteristics were evaluated. Statistical analyses included Poisson regression offset by person-year follow-up, chi-square tests for proportion t tests for means, and Kruskal-Wallis for medians.

    RESULTS AND LIMITATIONS: A total of 3027 patients (2932 unique individuals) were recruited (919 BRCA1 carriers, 709 BRCA1 noncarriers, 902 BRCA2 carriers, and 497 BRCA2 noncarriers). After 3 yr of screening, 527 men had PSA > 3.0 ng/ml, 357 biopsies were performed, and 112 PrCa cases were diagnosed (31 BRCA1 carriers, 19 BRCA1 noncarriers, 47 BRCA2 carriers, and 15 BRCA2 noncarriers). Higher compliance with biopsy was observed in BRCA2 carriers compared with noncarriers (73% vs 60%). Cancer incidence rate per 1000 person years was higher in BRCA2 carriers than in noncarriers (19.4 vs 12.0; p =  0.03); BRCA2 carriers were diagnosed at a younger age (61 vs 64 yr; p =  0.04) and were more likely to have clinically significant disease than BRCA2 noncarriers (77% vs 40%; p =  0.01). No differences in age or tumour characteristics were detected between BRCA1 carriers and BRCA1 noncarriers. The 4 kallikrein marker model discriminated better (area under the curve [AUC] = 0.73) for clinically significant cancer at biopsy than PSA alone (AUC = 0.65).

    CONCLUSIONS: After 3 yr of screening, compared with noncarriers, BRCA2 mutation carriers were associated with a higher incidence of PrCa, younger age of diagnosis, and clinically significant tumours. Therefore, systematic PSA screening is indicated for men with a BRCA2 mutation. Further follow-up is required to assess the role of screening in BRCA1 mutation carriers.

    PATIENT SUMMARY: We demonstrate that after 3 yr of prostate-specific antigen (PSA) testing, we detect more serious prostate cancers in men with BRCA2 mutations than in those without these mutations. We recommend that male BRCA2 carriers are offered systematic PSA screening.

  19. Yoon SY, Thong MK, Taib NA, Yip CH, Teo SH
    Fam Cancer, 2011 Jun;10(2):199-205.
    PMID: 21318382 DOI: 10.1007/s10689-011-9420-7
    Genetic counseling (GC) and genetic testing are vital risk management strategies in hereditary breast and ovarian cancer (HBOC) syndromes. Hitherto, cancer genetic testing amongst Asians has been described only in developed and high-income Asian countries. We studied the uptake and acceptance of GC and genetic testing services to Asian BRCA carriers in a middle-income country. A total of 363 patients were tested by full sequencing and large rearrangement analysis of both BRCA1 and BRCA2 genes in the Malaysian Breast Cancer (MyBrCa) Genetic Study. Of these, 49 index patients (13.5%) were found to carry deleterious mutations. GC pre- and post- result disclosures were provided and these groups of patients and their families were studied. GC and genetic testing were accepted by 82% of Malaysian patients at high risk for HBOC syndromes. However, risk assessment was limited by large, geographically dispersed, often polygamous or polyandrous families, and the lack of complete cancer registry. Cultural taboos about cancer diagnoses, social marginalization and lack of regulatory control of genetic discrimination were significant concerns. Only 78% of index patients informed their families of their risks and 11% of relatives came forward when offered free counseling and testing. Even when GC and genetic testing are provided at no cost, there remain significant societal and regulatory barriers to effective cancer genetic services in this underserved Asian population. Families believe there is a need for regulatory protection against genetic discrimination. Further studies are needed in the area of increasing awareness about the potential benefits of GC and genetic testing in Asians.
  20. Thirthagiri E, Cheong LS, Yip CH, Teo SH
    Fam Cancer, 2009;8(4):355-8.
    PMID: 19399639 DOI: 10.1007/s10689-009-9244-x
    A truncating mutation (1100delC) in the cell cycle checkpoint kinase-2 gene, CHEK2, has been identified as a risk factor for familial and sporadic breast cancer in some Northern and Western European populations. However, the prevalence of CHEK2*1100delC in breast cancer appears to be population dependent. We analysed the prevalence of CHEK2*1100delC in 668 breast cancer cases, of which 542 were invasive breast cancers, from a hospital-based cohort of breast cancer patients from Kuala Lumpur, Malaysia. The variant was not found in any patients in this cohort, suggesting that CHEK2*1100delC is rare in our population, and unlikely to contribute significantly to risk to breast cancer among the Malay, Chinese and Indian ethnic groups in Malaysia. This suggests that screening for this allele should not be routinely conducted in Malaysia.
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