Pharmacogenomics, biomarker network, and allele frequencies in colorectal cancer.

Colorectal cancer is one of the leading causes of cancer death worldwide. Over the last decades, several studies have shown that tumor-related genomic alterations predict tumor prognosis, drug response, and toxicity. These observations have led to the development of several therapies based on individual genomic profiles. As part of these approaches, pharmacogenomics analyses genomic alterations which may predict an efficient therapeutic response. Studying these mutations as biomarkers for predicting drug response is of a great interest to improve precision medicine. We conduct a comprehensive review of the main pharmacogenomics biomarkers and genomic alterations affecting enzyme activity, transporter capacity, channels, and receptors; and therefore the new advances in CRC precision medicine to select the best therapeutic strategy in populations worldwide, with a focus on Latin America.

State of Art of Cancer Pharmacogenomics in Latin American Populations.

Over the past decades, several studies have shown that tumor-related somatic and germline alterations predicts tumor prognosis, drug response and toxicity. Latin American populations present a vast geno-phenotypic diversity due to the great interethnic and interracial mixing. This genetic flow leads to the appearance of complex characteristics that allow individuals to adapt to endemic environments, such as high altitude or extreme tropical weather. These genetic changes, most of them subtle and unexplored, could establish a mutational profile to develop new pharmacogenomic therapies specific for Latin American populations. In this review, we present the current status of research on somatic and germline alterations in Latin America compared to those found in Caucasian and Asian populations.

Genetic Polymorphisms and Tumoral Mutational Profiles over Survival in Advanced Colorectal Cancer Patients: An Exploratory Study.

Colorectal cancer is a common disease, both in Chile and worldwide. The most widely used chemotherapy schemes are based on 5-fluorouracil (5FU) as the foundational drug (FOLFOX, CapeOX). Genetic polymorphisms have emerged as potential predictive biomarkers of response to chemotherapy, but conclusive evidence is lacking. This study aimed to investigate the role of genetic variants associated with 5FU-based chemotherapy on therapeutic response, considering their interaction with oncogene mutations (KRAS, NRAS, PI3KCA, AKT1, BRAF). In a retrospective cohort of 63 patients diagnosed with metastatic colorectal cancer, a multivariate analysis revealed that liver metastases, DPYD, ABCB1, and MTHFR polymorphisms are independent indicators of poor prognosis, irrespective of oncogene mutations. BRAF wild-type status and high-risk drug-metabolism polymorphisms correlated with a poor prognosis in this Chilean cohort. Additionally, findings from the genomics of drug sensitivity (GDSC) project demonstrated that cell lines with wild-type BRAF have higher IC50 values for 5-FU compared to BRAF-mutated cell lines. In conclusion, the genetic polymorphisms DPYDrs1801265, ABCB1rs1045642, and MTHFRrs180113 may serve as useful biomarkers for predicting a poor prognosis in patients undergoing 5-fluorouracil chemotherapy, regardless of oncogene mutations.

Pulmonary Inflammatory Response in Lethal COVID-19 Reveals Potential Therapeutic Targets and Drugs in Phases III/IV Clinical Trials.

Background: It is imperative to identify drugs that allow treating symptoms of severe COVID-19. Respiratory failure is the main cause of death in severe COVID-19 patients, and the host inflammatory response at the lungs remains poorly understood. Methods: Therefore, we retrieved data from post-mortem lungs from COVID-19 patients and performed in-depth in silico analyses of single-nucleus RNA sequencing data, inflammatory protein interactome network, and shortest pathways to physiological phenotypes to reveal potential therapeutic targets and drugs in advanced-stage COVID-19 clinical trials. Results: Herein, we analyzed transcriptomics data of 719 inflammatory response genes across 19 cell types (116,313 nuclei) from lung autopsies. The functional enrichment analysis of the 233 significantly expressed genes showed that the most relevant biological annotations were inflammatory response, innate immune response, cytokine production, interferon production, macrophage activation, blood coagulation, NLRP3 inflammasome complex, and the TLR, JAK-STAT, NF-κB, TNF, oncostatin M signaling pathways. Subsequently, we identified 34 essential inflammatory proteins with both high-confidence protein interactions and shortest pathways to inflammation, cell death, glycolysis, and angiogenesis. Conclusion: We propose three small molecules (baricitinib, eritoran, and montelukast) that can be considered for treating severe COVID-19 symptoms after being thoroughly evaluated in COVID-19 clinical trials.

Retrospective pharmacogenetic analysis of a pediatric patient under anticoagulant treatment: Clinical case / Análisis farmacogenético retrospectivo de una paciente pediátrica en tratamiento anticoagulante: caso clínico.

We present the clinical case of a 10-year-old patient diagnosed with dilated cardiomyopathy who registered INR values above 10 upon receiving standard doses of acenocoumarol, as well as other values reported as uncoagulable, forcing the discontinuation and restart of treatment more than once. Expected and stable INR levels were achieved after more than 30 days of treatment, surprisingly with half the recommended dose for a patient of her age and weight. We decided to conduct a retrospective pharmacogenomic analysis including nucleotide genetic polymorphisms (SNPs) with different degrees of association with the dose/response to antivitamin K (AVK) drugs: rs2108622 (gene CYP4F2), rs9923231, rs7294 (gene VKORC1), rs1799853, and rs1057910 (CYP2C9 gene) using TaqMan® RT-PCR. The patient was homozygous for rs9923231 (VKORC1) and heterozygous for rs2108622 (CYP4F2),a genetic profile strongly associated with a requirement of lower AVK doses as shown by national and international evidence. In conclusion, the pharmacogenetic analysis confirmed that this patient's genetic conditions, involving low expression of the VKA therapeutic target, required a lower dose than that established in clinical protocols as recommended by the Food and Drug Administration (FDA) and the PharmGKB® for coumarin drugs. A previous genotypic analysis of the patient would have allowed reaching the therapeutic range sooner, thus avoiding potential bleeding risks. This shows the importance of pharmacogenetic analyses for highly variable treatments with a narrow therapeutic range.

Se presenta el caso clínico de una paciente de 10 años diagnosticada con miocardiopatía dilatada, quien registró valores en el índice internacional normalizado (International Normalized Ratio, INR) superiores a 10 con la dosis estándar de acenocumarol, además de otros valores que indicaban el estado incoagulable, lo que obligó a suspender y reiniciar el tratamiento en varias ocasiones. Después de más de 30 días de tratamiento, sorprendentemente se lograron los niveles esperados y estables en el INR con la mitad de a dosis recomendada para una paciente de su edad y peso. Se decidió hacer un análisis farmacogenético retrospectivo del caso mediante RT-PCR con sondas TaqMan™ que incluyó cinco polimorfismos de un solo nucleótido y distinto grado de asociación con la dosis-respuesta a los fármacos antivitamínicos K (AVK): rs2108622 (gen CYP4F2), rs9923231, rs7294 (gen VKORC1), rs1799853 y rs1057910 (gen CYP2C9). La paciente resultó ser homocigota para el rs9923231 (VKORC1) y heterocigota para el rs2108622 (CYP4F2). Se ha evidenciado a nivel nacional e internacional que este perfil genético está fuertemente asociado con una necesidad de dosis menores de antivitamínicos K. En conclusión, el análisis farmacogenético confirmó que la condición genética de la paciente, la cual conlleva una baja expresión de la enzima VKORC1 (blanco terapéutico de los antivitamínicos K), hacía predecible la necesidad de una dosis menor a la establecida según los protocolos clínicos recomendados por la Food and Drug Administration (FDA) y PharmGKB™ para los fármacos cumarínicos.

In silico Analyses of Immune System Protein Interactome Network, Single-Cell RNA Sequencing of Human Tissues, and Artificial Neural Networks Reveal Potential Therapeutic Targets for Drug Repurposing Against COVID-19.

Background: There is pressing urgency to identify therapeutic targets and drugs that allow treating COVID-19 patients effectively. Methods: We performed in silico analyses of immune system protein interactome network, single-cell RNA sequencing of human tissues, and artificial neural networks to reveal potential therapeutic targets for drug repurposing against COVID-19. Results: We screened 1,584 high-confidence immune system proteins in ACE2 and TMPRSS2 co-expressing cells, finding 25 potential therapeutic targets significantly overexpressed in nasal goblet secretory cells, lung type II pneumocytes, and ileal absorptive enterocytes of patients with several immunopathologies. Then, we performed fully connected deep neural networks to find the best multitask classification model to predict the activity of 10,672 drugs, obtaining several approved drugs, compounds under investigation, and experimental compounds with the highest area under the receiver operating characteristics. Conclusion: After being effectively analyzed in clinical trials, these drugs can be considered for treatment of severe COVID-19 patients. Scripts can be downloaded at https://github.com/muntisa/immuno-drug-repurposing-COVID-19.

Genetic polymorphisms as non-modifiable susceptibility factors to laryngeal cancer.

Laryngeal squamous cell carcinoma (LSCC) is a highly disabling disease to the patient, affecting speech, swallowing and respiratory skills. Smoking and alcohol abuse are principal risk factors linked to this disease. Genetic factors can be involved in carcinogenesis by controlling the cell cycle, cell survival, angiogenesis, and invasiveness. Single nucleotide polymorphisms (SNPs) involving specific genes could modulate the risk of LSCC related to known carcinogens by modifying cellular responses, but not all genetic associations are known. In a case-control study, we assess the associations between cyclooxygenase-2 (COX2), epidermal growth factor (EGF), EGF receptor (EGFR), and tumor suppressor P53 SNPs on the risk of LSCC development in the Chilean population. A total of 85 LSCC patients and 95 healthy volunteers were recruited. SNPs genotype were analyzed from genomic DNA by Polymerase Chain Reaction (PCR)-Restriction Fragment Length Polymorphism (RFLP) and associations were estimated by odds ratios (ORs) using unconditional logistic regressions. A significant association between COX2 and TP53 SNP and LSCC risk was found, with an OR = 3.27 for COX2 c.-1329A>G (rs689466) SNP, and an OR = 1.94 for TP53 c.215C>G, Pro72Arg (rs1042522) SNP. These findings suggest that COX2 c.-1329A>G and TP53 c.215C>G (Pro72Arg) SNPs may be risk factors for LSCC. Through this research, we identify two low penetrance genetic variants that may be evaluated as novel biomarkers for this disease, in South American Mestizo populations.

A Pharmacogenetically Guided Acenocoumarol Dosing Algorithm for Chilean Patients: A Discovery Cohort Study.

BACKGROUND: Vitamin K antagonists (VKA) are used as prophylaxis for thromboembolic events in patients with cardiovascular diseases. The most common VKA are warfarin and acenocoumarol. These drugs have a narrow therapeutic margin and high inter-individual response variability due to clinical and pharmacogenetic variables. OBJECTIVE: The authors aim to develop an algorithm comprised of clinical and genetic factors to explain the variability in the therapeutic dose of acenocoumarol among Chilean patients. METHODOLOGY: DNA was obtained from 304 patients as a discovery cohort with an international normalized ratio (INR) range of 2.0-3.0. The non-genetic (demographic and clinical) variables were also recorded. Genotype analyses were performed using real-time PCR for VKORC1 (rs9923231), VKORC1 (rs7294), GGCx (rs11676382), CYP4F2 (rs2108622), ABCB1 (rs1045642), CYP2C9*2 (rs1799853), ApoE (rs429358), and CYP2C9*3 (rs1057910). RESULTS: The clinical variables that significantly influenced the weekly therapeutic dose of VKA were age, sex, body mass index (BMI), and initial INR, collectively accounting for 19% of the variability, and the genetic variables with a significant impact were VKORC1 (rs9923231), CYP2C9*2 (rs1799853), and CYP2C9*3 (rs1057910), explaining for another 37% of the variability. CONCLUSION: We developed an algorithm that explains 49.99% of the variability in therapeutic VKA dosage in the Chilean population studied. Factors that significantly affected the dosage included VKORC1, CYP2C9*2, and CYP2C9*3 polymorphisms, as well as age, sex, BMI, and initial INR.

Functionally Significant Coumarin-Related Variant Alleles and Time to Therapeutic Range in Chilean Cardiovascular Patients.

Despite the development of new oral agents over the last decade, vitamin K antagonists (VKAs) remain the most widely used anticoagulants for treating and preventing thromboembolism worldwide. In Chile, the Ministry of Health indicates that acenocoumarol should be used in preference to any other coumarin. Complications of inappropriate dosing are among the most frequently reported adverse events associated with this medication. It is well known that polymorphisms in pharmacokinetic and pharmacodynamic proteins related to coumarins (especially warfarin) influence response to these drugs. This work analyzed the impact of CYP2C19*2 (rs4244285), CYP1A2*1F (rs762551), GGCx (rs11676382), CYP2C9*2 (rs1799853), CYP2C9*3 (rs1057910), CYP4F2 (rs2108622), VKORC1 (rs9923231), VKORC1 (rs7294), CYP3A4*1B (rs2740574), and ABCB1 (rs1045642) polymorphisms on time to therapeutic range for oral anticoagulants in 304 Chilean patients. CYP2C9*3 polymorphisms were associated with time to therapeutic range for acenocoumarol in Chilean patients, and the CYP4F2 TT genotype, MDR1 A allele, CYP1A2 A allele, and CYP3A4T allele are promising variants that merit further analysis. The presence of polymorphisms explained only 4.1% of time to therapeutic range for acenocoumarol in a multivariate linear model. These results improve our understanding of the basis of ethnic variations in drug metabolism and response to oral anticoagulant therapy. We hope that these findings will contribute to developing an algorithm for VKA dose adjustment in the Chilean population in the near future, decreasing the frequency of stroke, systemic embolism, and bleeding-related adverse events.

Study of the allelic variants CYP2C9*2 and CYP2C9*3 in samples of the Peruvian mestizo population / Estudio de las variantes alélicas CYP2C9*2 y CYP2C9*3 en muestras de población mestiza peruana

Introduction: CYP2C9 metabolizes approximately 15% of the prescribed drugs. Its gene has alleles whose frequencies differ between ethnic groups and populations. The alleles CYP2C9*2 and CYP2C9*3 account for an enzyme with decreased activity and their frequencies have not been determined in the Peruvian mestizo population. Objective: To characterize the frequencies of the allelic variants *2 (rs1799853) and *3 (rs1057910) of CYP2C9 gen in the Peruvian mestizo population from Lima, Tacna y Junín. Materials and methods: We conducted an observational, prospective cross-sectional study with non-probabilistic, by convenience, and incidental sampling. We included 218 subjects according to the inclusion and exclusion criteria, all of whom had signed the informed consent. We obtained the genomic DNA from oral mucosa swab. For the detection of the CYP2C9*2 and CYP2C9*3 genotypes, we used real-time-polymerase chain reaction with TaqMan® probes. Results: The genotyping revealed that CYP2C9*2 and CYP2C9*3 variants have low frequencies (0.046 and 0.062, respectively). The frequency of intermediate metabolizers was 15.13% (CYP2C9*1/*2: 5.96%; CYP2C9*1/*3: 9.17%) and that of slow metabolizers was 3.22% (CYP2C9*2/*2: 1.38%; CYP2C9*3/*3: 1.38%; CYP2C9*2/*3: 0.46%). Conclusions: It was possible to determine the genotypic and allelic frequencies for the variants *2 and *3 of the CYP2C9 gene in a non-probabilistic sample of the Peruvian mestizo population. The frequencies obtained (0.046 and 0.062, respectively) corresponded to those expected for a South American mestizo population with Amerindian, European, African and Asian ancestry.

Introducción. El citocromo CYP2C9 metaboliza, aproximadamente, el 15 % de los fármacos prescritos. Su gen presenta alelos cuyas frecuencias difieren entre grupos étnicos y poblaciones. Los alelos CYP2C9*2 y CYP2C9*3 dan cuenta de una enzima con actividad disminuida cuya frecuencia no ha sido determinada en la población mestiza peruana. Objetivo. Caracterizar la frecuencia de las variantes *2 (rs1799853) y *3 (rs1057910) del gen CYP2C9 en muestras de población mestiza peruana provenientes de Lima, Tacna y Junín. Materiales y métodos. Se hizo un estudio descriptivo, observacional y prospectivo, con muestreo no probabilístico, por conveniencia e incidental. Se incluyeron 218 sujetos según los criterios de inclusión y exclusión; todos los participantes otorgaron su consentimiento informado. El ADN genómico se obtuvo mediante hisopado de mucosa oral, y la detección de los genotipos para los alelos CYP2C9*2 y CYP2C9*3 se hizo mediante reacción en cadena de la polimerasa (PCR) en tiempo real, utilizando sondas TaqMan™. Resultados. Las variantes de CYP2C9*2 y CYP2C9*3 están presentes en la población mestiza peruana con frecuencias de 0,046 y 0,062, respectivamente. El análisis de las frecuencias genotípicas observadas permitió predecir que la frecuencia de fenotipos metabolismo intermedio sería del 15,13 % (CYP2C9*1/*2: 5,96 %; CYP2C9*1/*3: 9,17 %), y la de fenotipos de metabolismo lento, del 3,22 % (CYP2C9*2/*2: 1,38 %; CYP2C9*3/*3: 1,38 %; CYP2C9*2/*3: 0,46 %). Conclusiones. Se lograron determinar las frecuencias genotípicas y alélicas para las variantes *2 y *3 del gen CYP2C9 en una muestra no probabilística de población mestiza peruana.

Análisis farmacogenético retrospectivo de una paciente pediátrica en tratamiento anticoagulante: caso clínico / Retrospective pharmacogenetic analysis of a pediatric patient under anticoagulant treatment: Clinical case

Se presenta el caso clínico de una paciente de 10 años diagnosticada con miocardiopatía dilatada, quien registró valores en el índice internacional normalizado (International Normalized Ratio, INR) superiores a 10 con la dosis estándar de acenocumarol, además de otros valores que indicaban el estado incoagulable, lo que obligó a suspender y reiniciar el tratamiento en varias ocasiones. Después de más de 30 días de tratamiento, sorprendentemente se lograron los niveles esperados y estables en el INR con la mitad de la dosis recomendada para una paciente de su edad y peso.Se decidió hacer un análisis farmacogenético retrospectivo del caso mediante RT-PCR con sondas TaqMan™ que incluyó cinco polimorfismos de un solo nucleótido y distinto grado de asociación con la dosis-respuesta a los fármacos antivitamínicos K (AVK): rs2108622 (gen CYP4F2), rs9923231, rs7294 (gen VKORC1), rs1799853 y rs1057910 (gen CYP2C9). La paciente resultó ser homocigota para el rs9923231 (VKORC1) y heterocigota para el rs2108622 (CYP4F2). Se ha evidenciado a nivel nacional e internacional que este perfil genético está fuertemente asociado con una necesidad de dosis menores de antivitamínicos K.En conclusión, el análisis farmacogenético confirmó que la condición genética de la paciente, la cual conlleva una baja expresión de la enzima VKORC1 (blanco terapéutico de los antivitamínicos K), hacía predecible la necesidad de una dosis menor a la establecida según los protocolos clínicos recomendados por la Food and Drug Administration (FDA) y PharmGKB™ para los fármacos cumarínicos. El análisis genotípico previo de la paciente hubiese permitido alcanzar el rango terapéutico más prontamente, evitando potenciales riesgos de hemorragia, lo que demuestra la importancia de los análisis farmacogenéticos en tratamientos de gran variabilidad y estrecho rango terapéutico.

Abstract We present the clinical case of a 10-year-old patient diagnosed with dilated cardiomyopathy who registered INR values above 10 upon receiving standard doses of acenocoumarol, as well as other values reported as uncoagulable, forcing the discontinuation and restart of treatment more than once. Expected and stable INR levels were achieved after more than 30 days of treatment, surprisingly with half the recommended dose for a patient of her age and weight. We decided to conduct a retrospective pharmacogenomic analysis including nucleotide genetic polymorphisms (SNPs) with different degrees of association with the dose/response to antivitamin K (AVK) drugs: rs2108622 (gene CYP4F2), rs9923231, rs7294 (gene VKORC1), rs1799853, and rs1057910 (CYP2C9 gene) using TaqMan® RT-PCR. The patient was homozygous for rs9923231 (VKORC1) and heterozygous for rs2108622 (CYP4F2), a genetic profile strongly associated with a requirement of lower AVK doses as shown by national and international evidence. In conclusion, the pharmacogenetic analysis confirmed that this patient's genetic conditions, involving low expression of the VKA therapeutic target, required a lower dose than that established in clinical protocols as recommended by the Food and Drug Administration (FDA) and the PharmGKB® for coumarin drugs. A previous genotypic analysis of the patient would have allowed reaching the therapeutic range sooner, thus avoiding potential bleeding risks. This shows the importance of pharmacogenetic analyses for highly variable treatments with a narrow therapeutic range.

Estudio de las variantes alélicas CYP2C9*2 y CYP2C9*3 en muestras de población mestiza peruana / Study of the allelic variants CYP2C9*2 and CYP2C9*3 in samples of the Peruvian mestizo population

Resumen Introducción. El citocromo CYP2C9 metaboliza, aproximadamente, el 15 % de los fármacos prescritos. Su gen presenta alelos cuyas frecuencias difieren entre grupos étnicos y poblaciones. Los alelos CYP2C9*2 y CYP2C9*3 dan cuenta de una enzima con actividad disminuida cuya frecuencia no ha sido determinada en la población mestiza peruana. Objetivo. Caracterizar la frecuencia de las variantes *2 (rs1799853) y *3 (rs1057910) del gen CYP2C9 en muestras de población mestiza peruana provenientes de Lima, Tacna y Junín. Materiales y métodos. Se hizo un estudio descriptivo, observacional y prospectivo, con muestreo no probabilístico, por conveniencia e incidental. Se incluyeron 218 sujetos según los criterios de inclusión y exclusión; todos los participantes otorgaron su consentimiento informado. El ADN genómico se obtuvo mediante hisopado de mucosa oral, y la detección de los genotipos para los alelos CYP2C9*2 y CYP2C9*3 se hizo mediante reacción en cadena de la polimerasa (PCR) en tiempo real, utilizando sondas TaqMan™. Resultados. Las variantes de CYP2C9*2 y CYP2C9*3 están presentes en la población mestiza peruana con frecuencias de 0,046 y 0,062, respectivamente. El análisis de las frecuencias genotípicas observadas permitió predecir que la frecuencia de fenotipos metabolismo intermedio sería del 15,13 % (CYP2C9*1/*2: 5,96 %; CYP2C9*1/*3: 9,17 %), y la de fenotipos de metabolismo lento, del 3,22 % (CYP2C9*2/*2: 1,38 %; CYP2C9*3/*3: 1,38 %; CYP2C9*2/*3: 0,46 %). Conclusiones. Se lograron determinar las frecuencias genotípicas y alélicas para las variantes *2 y *3 del gen CYP2C9 en una muestra no probabilística de población mestiza peruana. Las frecuencias obtenidas (0,046 y 0,062, respectivamente) están entre las esperadas para una población mestiza sudamericana con ascendencia amerindia, europea, africana y asiática.

Abstract Introduction: CYP2C9 metabolizes approximately 15% of the prescribed drugs. Its gene has alleles whose frequencies differ between ethnic groups and populations. The alleles CYP2C9*2 and CYP2C9*3 account for an enzyme with decreased activity and their frequencies have not been determined in the Peruvian mestizo population. Objective: To characterize the frequencies of the allelic variants *2 (rs1799853) and *3 (rs1057910) of CYP2C9 gen in the Peruvian mestizo population from Lima, Tacna y Junín. Materials and methods: We conducted an observational, prospective cross-sectional study with non-probabilistic, by convenience, and incidental sampling. We included 218 subjects according to the inclusion and exclusion criteria, all of whom had signed the informed consent. We obtained the genomic DNA from oral mucosa swab. For the detection of the CYP2C9*2 and CYP2C9*3 genotypes, we used real-time-polymerase chain reaction with TaqMan® probes. Results: The genotyping revealed that CYP2C9*2 and CYP2C9*3 variants have low frequencies (0.046 and 0.062, respectively). The frequency of intermediate metabolizers was 15.13% (CYP2C9*1/*2: 5.96%; CYP2C9*1/*3: 9.17%) and that of slow metabolizers was 3.22% (CYP2C9*2/*2: 1.38%; CYP2C9*3/*3: 1.38%; CYP2C9*2/*3: 0.46%). Conclusions: It was possible to determine the genotypic and allelic frequencies for the variants *2 and *3 of the CYP2C9 gene in a non-probabilistic sample of the Peruvian mestizo population. The frequencies obtained (0.046 and 0.062, respectively) corresponded to those expected for a South American mestizo population with Amerindian, European, African and Asian ancestry.

Perception of the usefulness of drug/gene pairs and barriers for pharmacogenomics in Latin America.

Pharmacogenetics and Pharmacogenomics areas are currently emerging fields focused to manage pharmacotherapy that may prevent undertreatment while avoiding associated drug toxicity in patients. Large international differences in the awareness and in the use of pharmacogenomic testing are presumed, but not well assessed to date. In the present study we review the awareness of Latin American scientific community about pharmacogenomic testing and the perceived barriers for their clinical application. In order to that, we have compiled information from 9 countries of the region using a structured survey which is compared with surveys previously performed in USA and Spain. The most relevant group of barriers was related to the need for clear guidelines for the use of pharmacogenomics in clinical practice, followed by insufficient awareness about pharmacogenomics among clinicians and the absence of regulatory institutions that facilitate the use of pharmacogenetic tests. The higher ranked pairs were TPMT/thioguanine, TPMT/azathioprine, CYP2C9/warfarin, UGT1A1/irinotecan, CYP2D6/amitriptiline, CYP2C19/citalopram and CYP2D6/clozapine. The lower ranked pairs were SLCO1B1/simvastatin, CYP2D6/metoprolol and GP6D/chloroquine. Compared with USA and Spanish surveys, 25 pairs were of lower importance for Latin American respondents. Only CYP2C19/esomeprazole, CYP2C19/omeprazole, CYP2C19/celecoxib and G6PD/dapsone were ranked higher or similarly to the USA and Spanish surveys. Integration of pharmacogenomics in clinical practice needs training of healthcare professionals and citizens, but in addition legal and regulatory guidelines and safeguards will be needed. We propose that the approach offered by pharmacogenomics should be incorporated into the decision-making plans in Latin America.