RESUMO
Pathological retinal angiogenesis profoundly impacts visual function in vascular eye diseases, such as retinopathy of prematurity (ROP) in preterm infants and age-related macular degeneration in the elderly. While the involvement of photoreceptors in these diseases is recognized, the underlying mechanisms remain unclear. This study delved into the pivotal role of photoreceptors in regulating abnormal retinal blood vessel growth using an oxygen-induced retinopathy (OIR) mouse model through the c-Fos/A disintegrin and metalloprotease 17 (Adam17) axis. Our findings revealed a significant induction of c-Fos expression in rod photoreceptors, and c-Fos depletion in these cells inhibited pathological neovascularization and reduced blood vessel leakage in the OIR mouse model. Mechanistically, c-Fos directly regulated the transcription of Adam17 a shedding protease responsible for the production of bioactive molecules involved in inflammation, angiogenesis, and cell adhesion and migration. Furthermore, we demonstrated the therapeutic potential by using an adeno-associated virus carrying a rod photoreceptor-specific short hairpin RNA against c-fos which effectively mitigated abnormal retinal blood vessel overgrowth, restored retinal thickness, and improved electroretinographic (ERG) responses. In conclusion, this study highlights the significance of photoreceptor c-Fos in ROP pathology, offering a novel perspective for the treatment of this disease.
Assuntos
Proteína ADAM17 , Proteínas Proto-Oncogênicas c-fos , Neovascularização Retiniana , Animais , Neovascularização Retiniana/metabolismo , Neovascularização Retiniana/patologia , Neovascularização Retiniana/genética , Proteína ADAM17/metabolismo , Proteína ADAM17/genética , Proteínas Proto-Oncogênicas c-fos/metabolismo , Proteínas Proto-Oncogênicas c-fos/genética , Camundongos , Humanos , Retinopatia da Prematuridade/metabolismo , Retinopatia da Prematuridade/patologia , Retinopatia da Prematuridade/genética , Camundongos Endogâmicos C57BL , Transcrição Gênica , Regulação da Expressão Gênica , Vasos Retinianos/metabolismo , Vasos Retinianos/patologia , Células Fotorreceptoras Retinianas Bastonetes/metabolismo , Células Fotorreceptoras Retinianas Bastonetes/patologia , Modelos Animais de Doenças , AngiogêneseRESUMO
Glutarimide-containing polyketides exhibiting potent antitumor and antimicrobial activities were encoded via conserved module blocks in various strains that favor the genomic mining of these family compounds. The bioinformatic analysis of the genome of Burkholderia gladioli ATCC 10248 showed a silent trans-AT PKS biosynthetic gene cluster (BGC) on chromosome 2 (Chr2C8), which was predicted to produce new glutarimide-containing derivatives. Then, the silent polyketide synthase gene cluster was successfully activated via in situ promoter insertion and heterologous expression. As a result, seven glutarimide-containing analogs, including five new ones, gladiofungins D-H (3-7), and two known gladiofungin A/gladiostatin (1) and 2 (named gladiofungin C), were isolated from the fermentation of the activated mutant. Their structures were elucidated through the analysis of HR-ESI-MS and NMR spectroscopy. The structural diversities of gladiofungins may be due to the degradation of the butenolide group in gladiofungin A (1) during the fermentation and extraction process. Bioactivity screening showed that 2 and 4 had moderate anti-inflammatory activities. Thus, genome mining combined with promoter engineering and heterologous expression were proved to be effective strategies for the pathway-specific activation of the silent BGCs for the directional discovery of new natural products.
Assuntos
Burkholderia gladioli , Piperidonas , Policetídeos , Burkholderia gladioli/genética , Burkholderia gladioli/metabolismo , Policetídeos/química , Piperidonas/química , Genômica , Família MultigênicaRESUMO
The broad bioactivities of nonribosomal peptides rely on increasing structural diversity. Genome mining of the Burkholderiales strain Schlegelella brevitalea DSM 7029 leads to the identification of a class of dodecapeptides, glidonins, that feature diverse N-terminal modifications and a uniform putrescine moiety at the C-terminus. The N-terminal diversity originates from the wide substrate selectivity of the initiation module. The C-terminal putrescine moiety is introduced by the unusual termination module 13, the condensation domain directly catalyzes the assembly of putrescine into the peptidyl backbone, and other domains are essential for stabilizing the protein structure. Swapping of this module to another two nonribosomal peptide synthetases leads to the addition of a putrescine to the C-terminus of related nonribosomal peptides, improving their hydrophilicity and bioactivity. This study elucidates the mechanism for putrescine addition and provides further insights to generate diverse and improved nonribosomal peptides by introducing a C-terminal putrescine.
Assuntos
Peptídeos , Putrescina , Peptídeos/genética , Peptídeos/química , Peptídeo Sintases/metabolismoRESUMO
Bacterial natural products (NPs) are an indispensable source of drugs and biopesticides. Heterologous expression is an essential method for discovering bacterial NPs and the efficient biosynthesis of valuable NPs, but the chassis for Gram-negative bacterial NPs remains inadequate. In this study, we built a Burkholderiales mutant Burkholderia gladioli Δgbn::attB by introducing an integrated site (attB) to inactivate the native gladiolin (gbn) biosynthetic gene cluster, which stabilizes large foreign gene clusters and reduces the native metabolite profile. The growth and successful heterologous production of high-value NPs such as phylogenetically close Burkholderiales-derived antitumor polyketides (PKs) rhizoxins, phylogenetically distant Gammaproteobacteria-derived anti-MRSA (methicillin-resistant Staphylococcus aureus) antibiotics WAP-8294As, and Deltaproteobacteria-derived antitumor PKs disorazols demonstrate that this strain is a potential chassis for Gram-negative bacterial NPs. We further improved the yields of WAP-8294As through promoter insertions and precursor pathway overexpression based on heterologous expression in this strain. This study provides a robust bacterial chassis for genome mining, efficient production, and molecular engineering of bacterial NPs.
Assuntos
Produtos Biológicos , Burkholderia gladioli , Staphylococcus aureus Resistente à Meticilina , Policetídeos , Burkholderia gladioli/genética , Burkholderia gladioli/metabolismo , Staphylococcus aureus Resistente à Meticilina/genética , Antibacterianos/farmacologia , Agentes de Controle Biológico , Policetídeos/metabolismo , Família MultigênicaRESUMO
Most transcriptome-wide association studies (TWASs) so far focus on European ancestry and lack diversity. To overcome this limitation, we aggregated genome-wide association study (GWAS) summary statistics, whole-genome sequences and expression quantitative trait locus (eQTL) data from diverse ancestries. We developed a new approach, TESLA (multi-ancestry integrative study using an optimal linear combination of association statistics), to integrate an eQTL dataset with a multi-ancestry GWAS. By exploiting shared phenotypic effects between ancestries and accommodating potential effect heterogeneities, TESLA improves power over other TWAS methods. When applied to tobacco use phenotypes, TESLA identified 273 new genes, up to 55% more compared with alternative TWAS methods. These hits and subsequent fine mapping using TESLA point to target genes with biological relevance. In silico drug-repurposing analyses highlight several drugs with known efficacy, including dextromethorphan and galantamine, and new drugs such as muscle relaxants that may be repurposed for treating nicotine addiction.
Assuntos
Reposicionamento de Medicamentos , Transcriptoma , Humanos , Transcriptoma/genética , Estudo de Associação Genômica Ampla/métodos , Uso de Tabaco , Biologia , Polimorfismo de Nucleotídeo Único/genética , Predisposição Genética para DoençaRESUMO
Tobacco and alcohol use are heritable behaviours associated with 15% and 5.3% of worldwide deaths, respectively, due largely to broad increased risk for disease and injury1-4. These substances are used across the globe, yet genome-wide association studies have focused largely on individuals of European ancestries5. Here we leveraged global genetic diversity across 3.4 million individuals from four major clines of global ancestry (approximately 21% non-European) to power the discovery and fine-mapping of genomic loci associated with tobacco and alcohol use, to inform function of these loci via ancestry-aware transcriptome-wide association studies, and to evaluate the genetic architecture and predictive power of polygenic risk within and across populations. We found that increases in sample size and genetic diversity improved locus identification and fine-mapping resolution, and that a large majority of the 3,823 associated variants (from 2,143 loci) showed consistent effect sizes across ancestry dimensions. However, polygenic risk scores developed in one ancestry performed poorly in others, highlighting the continued need to increase sample sizes of diverse ancestries to realize any potential benefit of polygenic prediction.
Assuntos
Consumo de Bebidas Alcoólicas , Predisposição Genética para Doença , Variação Genética , Internacionalidade , Herança Multifatorial , Uso de Tabaco , Humanos , Predisposição Genética para Doença/genética , Variação Genética/genética , Estudo de Associação Genômica Ampla/métodos , Herança Multifatorial/genética , Fatores de Risco , Uso de Tabaco/genética , Consumo de Bebidas Alcoólicas/genética , Transcriptoma , Tamanho da Amostra , Loci Gênicos/genética , Europa (Continente)/etnologiaRESUMO
Cancer is one of the most intractable diseases in the world because of its high recurrence rate, high metastasis rate and high lethality rate. Traditional chemotherapy, radiotherapy and surgery have unsatisfactory therapeutic effects and cause many severe side effects at the same time. Hydrogel is a new type of biomaterial with the advantages of good biocompatibility and easy degradation, which can be used as a carrier of functional nanomaterials for tumor therapy. Herein, we represent the progress of hydrogels with different skeletons and their application as carrier in tumor treatment. The hydrogels are listed as polyethylene glycol-based hydrogels, chitosan-based hydrogels, peptide-based hydrogels, hyaluronic acid-based hydrogels, steroid-based hydrogels and other hydrogels by skeletons, and their properties, modifications and toxicities were introduced. Some representative applications of combined hydrogels with nanomaterial for chemotherapy, photodynamic therapy, photothermal therapy, sonodynamic therapy, chemodynamic therapy and synergistic therapy are highlighted.
Assuntos
Quitosana , Neoplasias , Humanos , Hidrogéis , Ácido Hialurônico , Materiais Biocompatíveis , Neoplasias/tratamento farmacológicoRESUMO
OBJECTIVE: Previous studies found that arsenic exposures have been linked to prostate cancer risk. However, this finding has been inconsistent. The purpose of this paper was to estimate the effects of arsenic exposures on prostate cancer risk. METHOD: We conducted a meta-analysis of epidemiologic studies of arsenic exposures and prostate cancer risk. We searched for both arsenic exposure and prostate cancer studies published until January 2021 from the following electronic databases: PubMed, Scopus, and Web of Science. Multilevel meta-analysis via random-effects modeling was used to examine the association between arsenic exposures and prostate cancer risk. RESULTS: There were 12 studies included with an effect size of 23. Arsenic exposure was determined from water and soil (n = 8), urinary measurements (n = 2), or self-reported questionnaire (n = 2). Overall, arsenic exposure was found to be statistically significantly associated with prostate cancer risk (Relative risk [RR] = 1.18, 95% confidence interval [CI]: 1.06 - 1.30). In the sub-analysis, arsenic exposure from water and soil was found to be statistically significantly associated with prostate cancer risk (RR= 1.22, 95% CI: 1.05 - 1.41). CONCLUSION: Data suggest that arsenic exposures may play a role in increasing prostate cancer risk. Further prospective studies are warranted to verify the association between arsenic exposure and prostate cancer risk.
Assuntos
Arsênio , Neoplasias da Próstata , Arsênio/análise , Arsênio/toxicidade , Humanos , Masculino , Estudos Prospectivos , Neoplasias da Próstata/induzido quimicamente , Neoplasias da Próstata/epidemiologia , Solo , ÁguaRESUMO
Emerging noninvasive treatments, such as sonodynamic therapy (SDT) and chemodynamic therapy (CDT), have developed as promising alternatives or supplements to traditional chemotherapy. However, their therapeutic effects are limited by the hypoxic environment of tumors. Here, a biodegradable nanocomposite-mesoporous zeolitic-imidazolate-framework@MnO2 /doxorubicin hydrochloride (mZMD) is developed, which achieves enhanced SDT/CDT/chemotherapy through promoting oxidative stress and overcoming the multidrug resistance. The mZMD decomposes under both ultrasound (US) irradiation and specific reactions in the tumor microenvironment (TME). The mZM composite structure reduces the recombination rate of e- and h+ to improve SDT. MnO2 not only oxidizes glutathione in tumor cells to enhance oxidative stress, but also converts the endogenic H2 O2 into O2 to improve the hypoxic TME, which enhances the effects of chemotherapy/SDT. Meanwhile, the generated Mn2+ catalyzes the endogenic H2 O2 into ·OH for CDT, and acts as magnetic resonance imaging agent to guide therapy. In addition, dissociated Zn2+ further breaks the redox balance of TME, and co-inhibits the expression of P-glycoprotein (P-gp) with generated ROS to overcome drug resistance. Thus, the as-prepared intelligent biodegradable mZMD provides an innovative strategy to enhance SDT/CDT/chemotherapy.
Assuntos
Compostos de Manganês , Óxidos , Linhagem Celular Tumoral , Resistência a Múltiplos Medicamentos , Estresse Oxidativo , Óxidos/química , Microambiente TumoralRESUMO
Chemodynamic therapy (CDT) is an emerging approach to treat cancer based on the tumor microenvironment (TME), but its limited content of endogenous hydrogen peroxide (H2O2) weakens the anticancer effects. Herein, a multifunctional biomimetic nanozyme (Se@SiO2-Mn@Au/DOX, named as SSMA/DOX) is fabricated, which undergoes TME responsive self-cascade catalysis to facilitate MRI guided enhanced chemo/chemodynamic therapy. The SSMA/DOX nanocomposites (NCs) responsively degrade in acidic conditions of tumor to release Se, DOX, Au and Mn2+. Mn2+ not only enables MRI to guided therapy, but also catalyzes the endogenous H2O2 into hydroxyl radical (ËOH) for CDT. In addition, the Au NPs continuously catalyze glucose to generate H2O2, enhancing CDT by supplementing a sufficiently reactive material and cutting off the energy supply of the tumor by consuming glucose. Simultaneously, Se enhances the chemotherapy of doxorubicin hydrochloride (DOX) and CDT by upregulating ROS in the tumor cells, achieving remarkable inhibition effect towards tumor. Moreover, SSMA/DOX NCs have good biocompatibility and degradability, which avoid long-term toxicity and side effects. Overall, the degradable SSMA/DOX NCs provide an innovative strategy for tumor microenvironment responsive self-cascade catalysis to enhance tumor therapy.
Assuntos
Antineoplásicos/farmacologia , Doxorrubicina/farmacologia , Terapia Fototérmica , Neoplasias do Colo do Útero/tratamento farmacológico , Animais , Antineoplásicos/química , Materiais Biomiméticos/química , Materiais Biomiméticos/farmacologia , Catálise , Linhagem Celular , Doxorrubicina/química , Feminino , Ouro/química , Ouro/farmacologia , Humanos , Manganês/química , Manganês/farmacologia , Teste de Materiais , Ratos , Ratos Sprague-Dawley , Selênio/química , Selênio/farmacologia , Dióxido de Silício/química , Dióxido de Silício/farmacologia , Microambiente Tumoral/efeitos dos fármacosRESUMO
BACKGROUND: Inflammatory osteolysis, a major complication of total joint replacement surgery, can cause prosthesis failure and necessitate revision surgery. Macrophages are key effector immune cells in inflammatory responses, but excessive M1-polarization of dysfunctional macrophages leads to the secretion of proinflammatory cytokines and severe loss of bone tissue. Here, we report the development of macrophage-biomimetic porous SiO2-coated ultrasmall Se particles (porous Se@SiO2 nanospheres) to manage inflammatory osteolysis. RESULTS: Macrophage membrane-coated porous Se@SiO2 nanospheres(M-Se@SiO2) attenuated lipopolysaccharide (LPS)-induced inflammatory osteolysis via a dual-immunomodulatory effect. As macrophage membrane decoys, these nanoparticles reduced endotoxin levels and neutralized proinflammatory cytokines. Moreover, the release of Se could induce macrophage polarization toward the anti-inflammatory M2-phenotype. These effects were mediated via the inhibition of p65, p38, and extracellular signal-regulated kinase (ERK) signaling. Additionally, the immune environment created by M-Se@SiO2 reduced the inhibition of osteogenic differentiation caused by proinflammation cytokines, as confirmed through in vitro and in vivo experiments. CONCLUSION: Our findings suggest that M-Se@SiO2 have an immunomodulatory role in LPS-induced inflammation and bone remodeling, which demonstrates that M-Se@SiO2 are a promising engineered nanoplatform for the treatment of osteolysis occurring after arthroplasty.
Assuntos
Materiais Biomiméticos , Fatores Imunológicos , Macrófagos , Nanocompostos/química , Osteólise/metabolismo , Animais , Materiais Biomiméticos/química , Materiais Biomiméticos/farmacologia , Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/farmacologia , Citocinas/metabolismo , Modelos Animais de Doenças , Fatores Imunológicos/química , Fatores Imunológicos/farmacologia , Imunoterapia , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Camundongos , Porosidade , Células RAW 264.7 , Selênio/química , Selênio/farmacologia , Dióxido de Silício/química , Dióxido de Silício/farmacologiaRESUMO
Radiotherapy (RT) is a popular clinical therapy method for extending cancer patient survival, but is hampered by severe side effects and the weak therapy effect. Herein, responsive degradable selenium (Se) theranostic agents (Se@SiO2 @Bi nanocomposites (NCs)) are fabricated, which combine computed tomography (CT) imaging and simultaneously enhance the therapeutic effects of photothermal therapy (PTT) and RT, while reducing the side effects of radiation. The Se@SiO2 @Bi theranostic agents can accumulate at the tumor site, and responsively decompose to releease Se, avoiding systemic toxicity by the element. Se enhances the effect of PTT/RT, simultaneously reducing the side effects of RT. The Se@SiO2 @Bi NCs as CT agents also exhibit significantly enhanced contrast imaging performance due to the high atomic number of Bi. More importantly, the Se@SiO2 @Bi NCs can be rapidly excreted without long-term toxicity, owing to responsive degradation into ultrasmall particles (<5 nm) at the tumor site. In vitro and in vivo results show that the Se@SiO2 @Bi NCs can remarkably inhibit tumor cells, without causing appreciable toxicity during the treatment. This study opens a new perspective in rationally designing responsive degradable theranostic agents for future tumor therapy with enhanced therapeutic efficacy and lesser side effects.
Assuntos
Nanocompostos , Selênio , Humanos , Fototerapia , Medicina de Precisão , Dióxido de Silício , Nanomedicina TeranósticaRESUMO
There is great interest in understanding the impact of rare variants in human diseases using large sequence datasets. In deep sequence datasets of >10,000 samples, ~10% of the variant sites are observed to be multi-allelic. Many of the multi-allelic variants have been shown to be functional and disease-relevant. Proper analysis of multi-allelic variants is critical to the success of a sequencing study, but existing methods do not properly handle multi-allelic variants and can produce highly misleading association results. We discuss practical issues and methods to encode multi-allelic sites, conduct single-variant and gene-level association analyses, and perform meta-analysis for multi-allelic variants. We evaluated these methods through extensive simulations and the study of a large meta-analysis of ~18,000 samples on the cigarettes-per-day phenotype. We showed that our joint modeling approach provided an unbiased estimate of genetic effects, greatly improved the power of single-variant association tests among methods that can properly estimate allele effects, and enhanced gene-level tests over existing approaches. Software packages implementing these methods are available online.
Assuntos
Fumar Cigarros/genética , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla/estatística & dados numéricos , Doenças Raras/genética , Alelos , Interpretação Estatística de Dados , Feminino , Variação Genética/genética , Humanos , Masculino , Fenótipo , Polimorfismo de Nucleotídeo Único/genética , Doenças Raras/epidemiologia , Doenças Raras/patologiaRESUMO
The objectives were to determine the reference intervals of spot urine copper excretion indexes in pre-school children and to evaluate their utility in screening for Wilson disease (WD). With spot urine collected from a control sample of preschool children (aged 3-7 years, n=153), the reference intervals of spot urine copper excretion indexes and their biological variation were defined. In order to investigate their utility performance in screening for WD in this age group, multiple spot urine samples from six WD patients who were diagnosed at presymptomatic stage were also analysed and compared. Cut-off values useful for detection of WD were defined by receiver operator curve (ROC) analysis. Biological (inter-individual) variation of spot urine copper indexes expressed as coefficient of variation (CVg) were around 60% at this age group, which was moderate and similar to other clinically useful urine tests, such as urine albumin excretion ratio. Spot urine copper excretion strongly correlated with both urine creatinine and osmolality. Linear regression against both creatinine and osmolality showed that â¼94% of data points in healthy preschool children fell within the prediction interval, suggesting that both were useful normalisation factors. ROC showed that copper to osmolality ratio was the best index with an area under curve (AUC) greater than 0.98. Cut-off values of 0.5 µmol/L, 0.1 µmol/mmol and 0.00085 µmol/mOsmol (32 µg/L, 56 µg/g creatinine and 0.054 µg/mOsmol, respectively, in conventional units) for spot urine copper concentration, copper to creatinine ratio and copper to osmolality ratio, respectively, have potential application in the differentiation of WD patients. Based on the data, a new WD screening strategy targeting preschool children is proposed. Application of a bivariate screening strategy using spot urine copper concentration and urine osmolality may be useful in a population-wide screening program for WD among preschool children.
Assuntos
Cobre/urina , Degeneração Hepatolenticular/diagnóstico , Degeneração Hepatolenticular/urina , Urinálise/normas , Variação Biológica Individual , Criança , Pré-Escolar , Creatinina/urina , Feminino , Humanos , Masculino , Programas de Rastreamento/normas , Valores de ReferênciaRESUMO
A common GC polymorphism within miRNA-146a precursor region (rs2910164) has been associated with the risk of various cancers despite the underlying mechanism is unclear. In the current study, we aimed to examine the role of rs2910164 in the pathogenesis and predisposition to nasopharyngeal carcinoma (NPC). The GC polymorphism in 233 NPC patients, 173 matched controls and 3613 healthy elderly subjects in our locality were first determined using melting temperature (T(m))-shift allele-specific genotyping method. Results in our case-control study indicated that CC genotype was associated with the risk effect of NPC (adjusted odds ratio of GC + GG vs. CC, 0.49; 95% confidence interval, 0.35-0.69; P < 0.0001). Using real-time polymerase chain reaction (PCR) assay, we subsequently revealed that expressions of both miR-146a and its passenger strand (miR-146a*C or miR-146a*G) were increased in NPC samples (P < 0.001), albeit expression of miR-146a was not linked to the genotype. Furthermore, miR-146a*C in NPC was significantly increased in CC genotype (CC vs. GC, P = 0.038). Finally, we demonstrated by co-immunoprecipitation and luciferase reporter assays that all three miR-146a precursor-derived mature miRNAs interacted with Argonaute2 (Ago2) protein complex and could function as gene silencers. Taken together, our results showed that the variant C in rs2910164 was associated with the predisposition of NPC in Chinese population. This polymorphism may influence the risk of NPC by producing active mature miR-146a*C that regulate distinct set of target genes. These findings may enrich our understanding of how miRNA single nucleotide polymorphism affect NPC pathogenesis, and may have potential implications to improve NPC treatment in the future.
Assuntos
MicroRNAs/genética , Neoplasias Nasofaríngeas/etiologia , Polimorfismo de Nucleotídeo Único/genética , Idoso , Proteínas Argonautas/metabolismo , Biomarcadores Tumorais/genética , Carcinoma , Estudos de Casos e Controles , Feminino , Genótipo , Humanos , Imunoprecipitação , Luciferases/metabolismo , Masculino , Pessoa de Meia-Idade , Carcinoma Nasofaríngeo , Neoplasias Nasofaríngeas/metabolismo , Reação em Cadeia da Polimerase , Prognóstico , Fatores de RiscoRESUMO
BACKGROUND: Breast cancer patients regularly undergo adjuvant chemotherapies following surgery. However, these treatments are largely associated with chemotherapeutic toxicities ranging from nausea to severe myelosuppression. In this investigation, we examined the effects of four SNPs in NR1I2, CYP3A4 and CYP3A5 genes on chemotherapy-induced severe neutropenia in 311 female Chinese breast cancer patients undergoing a standard adjuvant chemotherapy regimen. METHODS: Patients were monitored for adverse reactions throughout the treatment, then divided into "none or mild" (80 %) or "severe" (20 %) toxicity groups according to whether they suffered grade 4 neutropenia defined as having an absolute neutrophil counts (ANC) of less than 0.5 × 10(9)/L anytime during the treatment. DNA was extracted from patients' peripheral blood samples, then genotyped using allele-specific Tm-shift PCR and melting analysis. RESULTS: Logistic regression revealed that rs776746 or CYP3A5*3 strongly associated with grade 4 neutropenia (OR = 2.56, P = 0.023) after adjustment for covariates, one of which more significant factor was baseline ANC (OR = 0.68, P = 0.020). Although univariate analysis in all patients did not reveal any association at first, further analysis indicated that rs776746 is significantly associated with severe neutropenia in subgroup of breast cancer patients with normal baseline ANC (≥2.0 × 10(9)/L). These carriers of A-allele have 3.14-fold increased risk of developing severe neutropenia (P = 0.004). CONCLUSION: Our results suggested that polymorphisms in CYP3A5 might be useful pharmacogenetic markers for the prediction of severe neutropenia during chemotherapy, however, only after screening patients by their baseline ANC in the presence of gene-environmental interaction. We demonstrate an approach of pharmacogenetic analysis, in which the genetic data should be analyzed in the perspective of other clinical parameters.