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Fulltext Clinical features and mutational analysis of X-linked agammaglobulinemia patients in Malaysia

Chear CT, Ismail IH, Chan KC, Noh LM, Kassim A, Latiff AHA, et al.

Front Immunol, 2023;14:1252765.
PMID: 37809070 DOI: 10.3389/fimmu.2023.1252765

BACKGROUND: Bruton's tyrosine kinase (BTK) is a cytoplasmic protein involved in the B cell development. X-linked agammaglobulinemia (XLA) is caused by mutation in the BTK gene, which results in very low or absent B cells. Affected males have markedly reduced immunoglobulin levels, which render them susceptible to recurrent and severe bacterial infections. Methods: Patients suspected with X-linked agammaglobulinemia were enrolled during the period of 2010-2018. Clinical summary, and immunological profiles of these patients were recorded. Peripheral blood samples were collected for monocyte BTK protein expression detection and BTK genetic analysis. The medical records between January 2020 and June 2023 were reviewed to investigate COVID-19 in XLA.
RESULTS: Twenty-two patients (from 16 unrelated families) were molecularly diagnosed as XLA. Genetic testing revealed fifteen distinct mutations, including four splicing mutations, four missense mutations, three nonsense mutations, three short deletions, and one large indel mutation. These mutations scattered throughout the BTK gene and mostly affected the kinase domain. All mutations including five novel mutations were predicted to be pathogenic or deleterious by in silico prediction tools. Genetic testing confirmed that eleven mothers and seven sisters were carriers for the disease, while three mutations were de novo. Flow cytometric analysis showed that thirteen patients had minimal BTK expression (0-15%) while eight patients had reduced BTK expression (16-64%). One patient was not tested for monocyte BTK expression due to insufficient sample. Pneumonia (n=13) was the most common manifestation, while Pseudomonas aeruginosa was the most frequently isolated pathogen from the patients (n=4). Mild or asymptomatic COVID-19 was reported in four patients.
CONCLUSION: This report provides the first overview of demographic, clinical, immunological and genetic data of XLA in Malaysia. The combination of flow cytometric assessment and BTK genetic analysis provides a definitive diagnosis for XLA patients, especially with atypical clinical presentation. In addition, it may also allow carrier detection and assist in genetic counselling and prenatal diagnosis.

Matched MeSH terms: Protein-Tyrosine Kinases/genetics
A novel BTK gene mutation creates a de-novo splice site in an X-linked agammaglobulinemia patient

Chear CT, Ripen AM, Mohamed SA, Dhaliwal JS

Gene, 2015 Apr 15;560(2):245-8.
PMID: 25680287 DOI: 10.1016/j.gene.2015.02.019

Bruton's tyrosine kinase (BTK), encoded by the BTK gene, is a cytoplasmic protein critical in B cell development. Mutations in the BTK gene cause X-linked agammaglobulinemia (XLA), a primary immunodeficiency with characteristically low or absent B cells and antibodies. This report describes a five year-old boy who presented with otitis externa, arthritis, reduced immunoglobulins and no B cells. Flow cytometry showed undetectable monocyte BTK expression. Sequencing revealed a novel mutation at exon 13 of the BTK gene which created a de novo splice site with a proximal 5 nucleotide loss resulting in a truncated BTK protein. The patient still suffered from ear infection despite intravenous immunoglobulin replacement therapy. In this study, mosaicism was seen only in the mother's genomic DNA. These results suggest that a combination of flow cytometry and BTK gene analysis is important for XLA diagnosis and carrier screening.

Matched MeSH terms: Protein-Tyrosine Kinases/genetics*
Fulltext A novel Bruton's tyrosine kinase gene (BTK) invariant splice site mutation in a Malaysian family with X-linked agammaglobulinemia

Chear CT, Gill HK, Ramly NH, Dhaliwal JS, Bujang N, Ripen AM, et al.

Asian Pac J Allergy Immunol, 2013 Dec;31(4):320-4.
PMID: 24383975 DOI: 10.12932/AP0304.31.4.2013

X-linked agammaglobulinemia (XLA) is a rare genetic disorder caused by mutations in the Bruton's tyrosine kinase (BTK) gene. These mutations cause defects in early B cell development. A patient with no circulating B cells and low serum immunoglobulin isotypes was studied as were his mother and sister. Monocyte BTK protein expression was evaluated by flow cytometry. The mutation was determined using PCR and followed by sequencing. Flow cytometry showed the patient lacked BTK protein expression in his monocytes while the mother and sister had 62% and 40% of the monocytes showing BTK protein expressions respectively. The patient had a novel base substitution in the first nucleotide of intron 9 in the BTK gene, and the mutation was IVS9+1G

Matched MeSH terms: Protein-Tyrosine Kinases/genetics*
Fulltext Immunohistochemical localization of RET rearrangements in a Malaysian papillary thyroid carcinoma population

Omar E, Othman NH

Med J Malaysia, 2003 Aug;58(3):461-2.
PMID: 14750392
Matched MeSH terms: Receptor Protein-Tyrosine Kinases/genetics*
Fulltext Diagnostic work-up and systemic treatment for advanced non-squamous non-small-cell lung cancer in four Southeast Asian countries

Soo R, Mery L, Bardot A, Kanesvaran R, Keong TC, Pongnikorn D, et al.

ESMO Open, 2022 Oct;7(5):100560.
PMID: 35988454 DOI: 10.1016/j.esmoop.2022.100560

BACKGROUND: Lung cancer is the second most common cancer and leading cause of cancer mortality worldwide. Recent advances in molecular testing and targeted therapy have improved survival among patients with metastatic non-small-cell lung cancer (NSCLC). We sought to quantify and describe molecular testing among metastatic non-squamous NSCLC cases in selected Southeast Asian countries and describe first-line therapy chosen.
PATIENTS AND METHODS: A retrospective study was conducted based on incident lung cancer cases diagnosed between 2017 and 2019 in Lampang (Thailand), Penang (Malaysia), Singapore and Yogyakarta (Indonesia). Cases (n = 3413) were defined using the International Classification of Diseases for Oncology third edition. In Singapore, a clinical series obtained from the National Cancer Centre was used to identify patients, while corresponding population-based cancer registries were used elsewhere. Tumor and clinical information were abstracted by chart review according to a predefined study protocol. Molecular testing of epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK) gene rearrangement, ROS1 gene rearrangement and BRAF V600 mutation was recorded.
RESULTS: Among 2962 cases with a specified pathological diagnosis (86.8%), most patients had non-squamous NSCLC (75.8%). For cases with staging information (92.1%), the majority presented with metastatic disease (71.3%). Overall, molecular testing rates in the 1528 patients with stage IV non-squamous NSCLC were 67.0% for EGFR, 42.3% for ALK, 39.1% for ROS1, 7.8% for BRAF and 36.1% for PD-L1. Among these patients, first-line systemic treatment included chemotherapy (25.9%), targeted therapy (35.6%) and immunotherapy (5.9%), with 31% of patients having no record of antitumor treatment. Molecular testing and the proportion of patients receiving treatment were highly heterogenous between the regions.
CONCLUSIONS: This first analysis of data from a clinically annotated registry for lung cancer from four settings in Southeast Asia has demonstrated the feasibility of integrating clinical data within population-based cancer registries. Our study results identify areas where further development could improve patient access to optimal treatment.

Matched MeSH terms: Protein-Tyrosine Kinases/genetics
Parallel genome-wide RNAi screens identify lymphocyte-specific protein tyrosine kinase (LCK) as a targetable vulnerability of cell proliferation and chemoresistance in nasopharyngeal carcinoma

Liew K, Yu GQS, Wei Pua LJ, Wong LZ, Tham SY, Hii LW, et al.

Cancer Lett, 2021 Apr 28;504:81-90.
PMID: 33587980 DOI: 10.1016/j.canlet.2021.02.006

Despite recent in advances in the management of nasopharyngeal carcinoma (NPC), development of targeted therapy remains challenging particularly in patients with recurrent or metastatic disease. To search for clinically relevant targets for the treatment of NPC, we carried out parallel genome-wide functional screens to identified essential genes that are required for NPC cells proliferation and cisplatin resistance. We identified lymphocyte-specific protein tyrosine kinase (LCK) as a key vulnerability of both proliferation and cisplatin resistance. Depletion of endogenous LCK or treatment of cells with LCK inhibitor induced tumor-specific cell death and synergized cisplatin sensitivity in EBV-positive C666-1 and EBV-negative SUNE1 cells. Further analyses demonstrated that LCK is regulating the proliferation and cisplatin resistance through activation of signal transducer and activator of transcription 5 (STAT5). Taken together, our study provides a molecular basis for targeting LCK and STAT5 signaling as potential druggable targets for the management of NPC.

Matched MeSH terms: Protein-Tyrosine Kinases/genetics*
Common ALK gene rearrangement in Asian CD30+ anaplastic large cell lymphoma: an immunohistochemical and fluorescence in situ hybridisation (FISH) study on paraffin-embedded tissue

Tai YC, Kim LH, Peh SC

Pathology, 2003 Oct;35(5):436-43.
PMID: 14555389

AIMS: The most common recurrent genetic aberration in anaplastic large cell lymphoma (ALCL) is translocation involving the ALK gene that results in ectopic expression of ALK protein in lymphoid tissue. This study aims to investigate the frequency of ALK gene rearrangement in a series of Asian ALCL.
METHODS: ALK gene rearrangement was detected by immunostaining of ALK protein and fluorescence in situ hybridisation (FISH) targeting at the 2p23 region.
RESULTS: The expression of ALK protein was detected in 24/34 (71%) of the cases, and it was significantly higher in childhood cases (100%) when compared to adult cases (47%). The analyses by FISH were consistent with the results from immunostaining of ALK protein, but the analyses were only successful in 15/34 (44%) cases. FISH analyses detected extra copies of ALK gene in three cases, including one case that expressed ALK protein and showed 2p23 rearrangement.
CONCLUSIONS: The current series revealed a high frequency of ALK gene rearrangement, especially in the children. Immunostaining of ALK protein is a reliable indication of ALK gene rearrangement, and is superior to FISH. However, FISH analysis is useful in detecting other genetic aberrations that are not related to ALK gene rearrangement.

Matched MeSH terms: Protein-Tyrosine Kinases/genetics*
Knockdown of ROS1 gene sensitizes breast tumor growth to doxorubicin in a syngeneic mouse model

Tiash S, Chua MJ, Chowdhury EH

Int J Oncol, 2016 Jun;48(6):2359-66.
PMID: 27035628 DOI: 10.3892/ijo.2016.3452

Treatment of breast cancer, the second leading cause of female deaths worldwide, with classical drugs is often accompanied by treatment failure and relapse of disease condition. Development of chemoresistance and drug toxicity compels compromising the drug concentration below the threshold level with the consequence of therapeutic inefficacy. Moreover, amplification and over-activation of proto-oncogenes in tumor cells make the treatment more challenging. The oncogene, ROS1 which is highly expressed in diverse types of cancers including breast carcinoma, functions as a survival protein aiding cancer progression. Thus we speculated that selective silencing of ROS1 gene by carrier-mediated delivery of siRNA might sensitize the cancer cells to the classical drugs at a relatively low concentration. In this investigation we showed that intracellular delivery of c-ROS1-targeting siRNA using pH-sensitive inorganic nanoparticles of carbonate apatite sensitizes mouse breast cancer cells (4T1) to doxorubicin, but not to cisplatin or paclitaxel, with the highest enhancement in chemosensitivity obtained at 40 nM of the drug concentration. Although intravenous administrations of ROS1-loaded nanoparticles reduced growth of the tumor, a further substantial effect on growth retardation was noted when the mice were treated with the siRNA- and Dox-bound particles, thus suggesting that silencing of ROS1 gene could sensitize the mouse breast cancer cells both in vitro and in vivo to doxorubicin as a result of synergistic effect of the gene knockdown and the drug action, eventually preventing activation of the survival pathway protein, AKT1. Our findings therefore provide valuable insight into the potential cross-talk between the pathways of ROS1 and doxorubicin for future development of effective therapeutics for breast cancer.

Matched MeSH terms: Receptor Protein-Tyrosine Kinases/genetics*
Molecular process of glucose uptake and glycogen storage due to hamamelitannin via insulin signalling cascade in glucose metabolism

Issac PK, Guru A, Chandrakumar SS, Lite C, Saraswathi NT, Arasu MV, et al.

Mol Biol Rep, 2020 Sep;47(9):6727-6740.
PMID: 32809102 DOI: 10.1007/s11033-020-05728-5

Understanding the mechanism by which the exogenous biomolecule modulates the GLUT-4 signalling cascade along with the information on glucose metabolism is essential for finding solutions to increasing cases of diabetes and metabolic disease. This study aimed at investigating the effect of hamamelitannin on glycogen synthesis in an insulin resistance model using L6 myotubes. Glucose uptake was determined using 2-deoxy-D-[1-3H] glucose and glycogen synthesis were also estimated in L6 myotubes. The expression levels of key genes and proteins involved in the insulin-signaling pathway were determined using real-time PCR and western blot techniques. The cells treated with various concentrations of hamamelitannin (20 µM to 100 µM) for 24 h showed that, the exposure of hamamelitannin was not cytotoxic to L6 myotubes. Further the 2-deoxy-D-[1-3H] glucose uptake assay was carried out in the presence of wortmannin and Genistein inhibitor for studying the GLUT-4 dependent cell surface recruitment. Hamamelitannin exhibited anti-diabetic activity by displaying a significant increase in glucose uptake (125.1%) and glycogen storage (8.7 mM) in a dose-dependent manner. The optimum concentration evincing maximum activity was found to be 100 µm. In addition, the expression of key genes and proteins involved in the insulin signaling pathway was studied to be upregulated by hamamelitannin treatment. Western blot analysis confirmed the translocation of GLUT-4 protein from an intracellular pool to the plasma membrane. Therefore, it can be conceived that hamamelitannin exhibited an insulinomimetic effect by enhancing the glucose uptake and its further conversion into glycogen by regulating glucose metabolism.

Matched MeSH terms: Protein-Tyrosine Kinases/genetics