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9 result(s) for "Tan, Iain B. H."
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Risk of hepatitis B virus (HBV) reactivation in hepatitis B surface antigen negative/hepatitis B core antibody positive patients receiving rituximab-containing combination chemotherapy without routine antiviral prophylaxis
The use of rituximab has been associated with increased risk of hepatitis B virus (HBV) reactivation in patients who are hepatitis B surface antigen (HBsAg) negative and antihepatitis B core antibody (anti-HBc) positive. We aim to determine the rate of HBV reactivation in this group of patients who received rituximab-containing combination chemotherapy without concomitant antiviral prophylaxis and to identify potential risk factors for reactivation. Sixty-two HBsAg negative/anti-HBc positive patients with B-cell lymphoma treated with rituximab-based immunochemotherapy from 2006 to 2009 were included. None of the patients received concomitant antiviral prophylaxis. In this cohort, 48 (77%) patients received rituximab with cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP), eight (13%) received rituximab with cyclophosphamide, vincristine and prednisolone, and six (10%) received other chemotherapy regimens. Two patients suffered HBV reactivation; both were above 70 years of age, received R-CHOP chemotherapy and were negative for antihepatitis B surface antibody (anti-HBs) at baseline. One of the two patients reactivated shortly after completion of R-CHOP chemotherapy while the other reactivated during rituximab maintenance treatment. Thus, the overall reactivation rate in this cohort of patients is 3% (2/62), 4% (2/48), and 25% (1/4) in patients who received R-CHOP chemotherapy and who received rituximab maintenance, respectively. The rate of HBV reactivation is low in patients who are HBsAg negative/anti-HBc positive receiving rituximab-based combination chemotherapy without concomitant antiviral prophylaxis. However, elderly patients, particularly those without anti-HBs, seemed particularly at risk.
Phenotype-driven precision oncology as a guide for clinical decisions one patient at a time
Genomics-driven cancer therapeutics has gained prominence in personalized cancer treatment. However, its utility in indications lacking biomarker-driven treatment strategies remains limited. Here we present a “phenotype-driven precision-oncology” approach, based on the notion that biological response to perturbations, chemical or genetic, in ex vivo patient-individualized models can serve as predictive biomarkers for therapeutic response in the clinic. We generated a library of “screenable” patient-derived primary cultures (PDCs) for head and neck squamous cell carcinomas that reproducibly predicted treatment response in matched patient-derived-xenograft models. Importantly, PDCs could guide clinical practice and predict tumour progression in two n  = 1 co-clinical trials. Comprehensive “-omics” interrogation of PDCs derived from one of these models revealed YAP1 as a putative biomarker for treatment response and survival in ~24% of oral squamous cell carcinoma. We envision that scaling of the proposed PDC approach could uncover biomarkers for therapeutic stratification and guide real-time therapeutic decisions in the future. Treatment response in patient-derived models may serve as a biomarker for response in the clinic. Here, the authors use paired patient-derived mouse xenografts and patient-derived primary culture models from head and neck squamous cell carcinomas, including metastasis, as models for high-throughput screening of anti-cancer drugs.
Spatial profiling of gastric cancer patient-matched primary and locoregional metastases reveals principles of tumour dissemination
ObjectiveEndoscopic mucosal biopsies of primary gastric cancers (GCs) are used to guide diagnosis, biomarker testing and treatment. Spatial intratumoural heterogeneity (ITH) may influence biopsy-derived information. We aimed to study ITH of primary GCs and matched lymph node metastasis (LNmet).DesignGC resection samples were annotated to identify primary tumour superficial (PTsup), primary tumour deep (PTdeep) and LNmet subregions. For each subregion, we determined (1) transcriptomic profiles (NanoString ‘PanCancer Progression Panel’, 770 genes); (2) next-generation sequencing (NGS, 225 gastrointestinal cancer-related genes); (3) DNA copy number profiles by multiplex ligation-dependent probe amplification (MLPA, 16 genes); and (4) histomorphological phenotypes.ResultsNanoString profiling of 64 GCs revealed no differences between PTsup1 and PTsup2, while 43% of genes were differentially expressed between PTsup versus PTdeep and 38% in PTsup versus LNmet. Only 16% of genes were differently expressed between PTdeep and LNmet. Several genes with therapeutic potential (eg IGF1, PIK3CD and TGFB1) were overexpressed in LNmet and PTdeep compared with PTsup. NGS data revealed orthogonal support of NanoString results with 40% mutations present in PTdeep and/or LNmet, but not in PTsup. Conversely, only 6% of mutations were present in PTsup and were absent in PTdeep and LNmet. MLPA demonstrated significant ITH between subregions and progressive genomic changes from PTsup to PTdeep/LNmet.ConclusionIn GC, regional lymph node metastases are likely to originate from deeper subregions of the primary tumour. Future clinical trials of novel targeted therapies must consider assessment of deeper subregions of the primary tumour and/or metastases as several therapeutically relevant genes are only mutated, overexpressed or amplified in these regions.
Breast cancer in women with neurofibromatosis type 1 (NF1): a comprehensive case series with molecular insights into its aggressive phenotype
PurposeThe purpose of the study was to improve the understanding of NF1-associated breast cancer, given the increased risk of breast cancer in this tumour predisposition syndrome and the limited data.MethodsWe identified 18 women with NF1 and breast cancer at our institution. Clinical and pathologic characteristics of NF1-associated breast cancers were compared with 7132 breast cancers in patients without NF1 from our institutional database. Next generation sequencing was performed on DNA from blood and breast cancer specimens available. Blood specimens negative for NF1 mutation were subjected to multiplex ligation-dependent probe amplification (MLPA) to identify complete/partial deletions or duplications. Expression of neurofibromin in the NF1-associated breast cancers was evaluated using immunohistochemistry.ResultsThere was a higher frequency of grade 3 (83.3% vs 45.4%, p = 0.005), oestrogen receptor (ER) negative (66.7% vs 26.3%, p < 0.001) and human epidermal growth factor receptor 2 (HER2)-positive (66.7% vs 23.4%, p < 0.001) tumours among NF1 patients compared to non-NF1 breast cancers. Overall survival was inferior in NF1 patients in multivariable analysis (hazard ratio 2.25, 95% CI 1.11–4.60; p = 0.025). Apart from germline NF1 mutations (11/16; 69%), somatic mutations in TP53 (8/10; 80%), second-hit NF1 (2/10; 20%), KMT2C (4/10; 40%), KMT2D (2/10; 20%), and PIK3CA (2/10; 20%) were observed. Immunohistochemical expression of neurofibromin was seen in the nuclei and/or cytoplasm of all specimens, but without any consistent pattern in the intensity or extent.ConclusionsThis comprehensive series of NF1-associated breast cancers suggests that their aggressive features are related to germline NF1 mutations in cooperation with somatic mutations in TP53, KMT2C and other genes.
Preoperative Prognostic Factors After Liver Resection for Non-Colorectal, Non-Neuroendocrine Liver Metastases and Validation of the Adam Score in an Asian Population
Background Historically, the benefit of liver resection for non-colorectal, non-neuroendocrine (NCNN) liver metastases has been controversial. This study aims to determine the preoperative prognostic factors of liver resection for NCNN liver metastases and validate the Adam score in an Asian population. Methods Consecutive patients who underwent liver resection for NCNN liver metastases were identified retrospectively from a prospective liver resection database of the single institution between 2001 and 2014. Univariate Cox regression models were used to identify associations with outcome variables. Recurrence-free interval and overall survival were determined using the Kaplan–Meier method and compared using log-rank test. Results Seventy-eight consecutive patients were identified, which met the study criteria. Univariate analysis demonstrated that adenocarcinoma histology of primary cancer, disease-free interval and number of nodules were significant predictors of survival. Four of the six components of Adam score were significant predictors of survival. These were the presence of extrahepatic metastases, R2 resection, disease-free interval and type of a primary tumour. The total Adam score was also a significant predictor of survival. Conclusion Liver resection for NCNN liver metastases is a safe and viable treatment option in carefully selected patients. Significant preoperative prognostic factors include adenocarcinoma primary tumours, disease-free interval and number of nodules. The total Adam score was a good predictor of overall survival and can be used to risk stratify patients undergoing hepatic resection for NCNN liver metastases.
Osteoradionecrosis of the cervical spine complicated by pneumocephalus and meningitis in a nasopharyngeal cancer patient radically treated with radiotherapy 11 years ago
Superimposed infection of osteoradionecrotic cervical spine with cranial extension is difficult to treat and potentially fatal. This report describes the case of a middle-aged Chinese man 11 years post radical radiotherapy for nasopharyngeal cancer with no evidence of disease presenting initially with neck pain secondary to cervical osteoradionecrosis. He was re-admitted a month later with aspiration pneumonia associated with Streptococcus milleri bacteraemia, complicated by septic shock. The last re-admission was 2 months later with fever, expressive dysphasia and right upper motor neuron signs. There was interval increase of dental and peridental soft tissue mass, interval widening of atlantodental distance on MRI cervical spine associated with pneumocephalus, meningeal enhancement and pre-pontine soft tissue mass on CT brain consistent with infected osteoradionecrotic cervical spine complicated by cranial extension. The patient also had concomitant bilateral pneumonia and subsequently passed away from fulminant sepsis.
Designing a Self-Contained Qualitative Analysis Test for Transition Metal Ions
A challenging self-contained qualitative analysis test for transition metal compounds comprising nine unknowns was designed whereby the unknown solutions can be systematically identified, without relying on external reagents, by inter-mixing the unknown samples. The names of the samples are made known, but their correspondence with the samples is concealed. A representative range of transition metal compounds was selected, together with two complementary main-group compounds. This \"9-bottle\" test encourages logical deduction and analytical thinking and cannot be negotiated by pure regurgitation of memorized facts. It is also more environment-friendly as it avoids the use of any external reagents, thereby reducing waste and circumventing the disposal problems.
Dynamic expression of tRNA-derived small RNAs define cellular states
Transfer RNA (tRNA)-derived small RNAs (tsRNAs) have recently emerged as important regulators of protein translation and shown to have diverse biological functions. However, the underlying cellular and molecular mechanisms of tsRNA function in the context of dynamic cell-state transitions remain unclear. Here we report the identification of a set of tsRNAs upregulated in differentiating mouse embryonic stem cells (mESCs). Mechanistic analyses revealed primary functions of tsRNAs in regulating polysome assembly and translation. Notably, interactome studies with differentially-enriched tsRNAs revealed a switch in associations with 'effector' RNPs and 'target' mRNAs in different cell-states. We also demonstrate that a specific pool of tsRNAs can interact with Igf2bp1, an RNA-binding protein, to influence the expression of the pluripotency-promoting factor-c-Myc, thereby providing evidence for tsRNAs in modulating stem cell-states in mESCs. Finally, tsRNA expression analyses in distinct, heterologous cell and tissue models of stem/transformed versus differentiated/normal states reveal that tsRNA-mediated regulation of protein translation may represent a global biological phenomenon associated with cell-state transitions.
Detection of genomic alterations in breast cancer with circulating tumour DNA sequencing
Analysis of circulating cell-free DNA (cfDNA) has opened new opportunities for characterizing tumour mutational landscapes with many applications in genomic-driven oncology. We developed a customized targeted cfDNA sequencing approach for breast cancer (BC) using unique molecular identifiers (UMIs) for error correction. Our assay, spanning a 284.5 kb target region, is combined with a novel freely-licensed bioinformatics pipeline that provides detection of low-frequency variants, and reliable identification of copy number variations (CNVs) directly from plasma DNA. We first evaluated our pipeline on reference samples. Then in a cohort of 35 BC patients our approach detected actionable driver and clonal variants at low variant frequency levels in cfDNA that were concordant (77%) with sequencing of primary and/or metastatic solid tumour sites. We also detected ERRB2 gene CNVs used for HER2 subtype classification with 80% precision compared to immunohistochemistry. Further, we evaluated fragmentation profiles of cfDNA in BC and observed distinct differences compared to data from healthy individuals. Our results show that the developed assay addresses the majority of tumour associated aberrations directly from plasma DNA, and thus may be used to elucidate genomic alterations in liquid biopsy studies.