Chondroblastomas in Children and Young Adults: Revision of 55 Cases.

BACKGROUND: Chondroblastomas are uncommon primary bone tumors localized in long bone epiphyses in children and young adults. The risk of metastasis is rare, but they have a high capacity for local recurrence. Surgical curettage with bone grafting or bone substitute is the preferred treatment. METHODS: We performed an observational retrospective study of chondroblastomas treated in 2 hospitals in Barcelona from 1988 to 2018. We reviewed the location of the tumor, clinical presentation, imaging, histopathology, initial treatment, and cases of recurrence with a review of their treatment. We assessed the correlation between recurrence and index surgery, anatomic location, and certain histopathologic findings (presence of mitotic figures, necrosis, and positivity for protein S-100). RESULTS: The series included 55 patients treated from 1988 to 2018, with ages ranging from 6 to 26, and a mean follow-up of 6.1 years (±3.7). The most common location was the distal femur metaphyseal/epiphyseal region. The most frequent clinical presentation was pain in the affected. Forty-five cases (81.8%) were treated with curettage of the tumor, and 4 cases (7.3%) with a wide resection. Forty-two cases (85.7%) received bone substitutes after curettage or resection. We found 5 cases of recurrence (9.1% recurrence rate); however, we could not find a statistically significant correlation between index surgery and recurrence ( P =0.24), anatomic location and recurrence ( P =0.49), or recurrence and histopathologic findings (mitotic figures, P =0.49; necrosis, P =0.60; positivity for protein S-100, P =0.52). In all the cases the treatment for the local recurrence was surgical, with a final healing rate of 100%. CONCLUSIONS: Chondroblastomas should be considered in children and adolescents when presenting with pain and an image suggestive of a tumoral lesion on plain x-ray, most frequently in epiphyses of long bones.Surgical treatment is preferred, obtaining good results after curettage and bone substitute. Chondroblastomas are tumors with a high capacity for recurrence, therefore an adequate surgical technique and surgeon experience are paramount to achieve good outcomes. LEVEL OF EVIDENCE: Level IV (case series). Therapeutic studies-investigating results or treatment.

Is hip resection arthroplasty a successful definitive treatment?

Purpose: Hip resection arthroplasty as a definitive treatment is an uncommon indication, although still in use selectively. This study evaluates a cohort of patients who have undergone hip resection arthroplasty surgery indicated as a definitive treatment, in order to assess the rate of re-operation, the rate of infection, and the mortality rates. Methods: We conducted a retrospective, observational, descriptive analysis of a cohort of patients who had undergone a hip resection arthroplasty intended as a definitive treatment, in two University Hospitals from 1994 to 2020. The exclusion criteria were the implantation of a hip cement spacer, or a temporary hip resection arthroplasty in patients undergoing a two-staged surgical approach. We found 26 cases of hip resection arthroplasty. We recorded the indications for a definitive hip resection arthroplasty, the outcomes and complications, and analyzed the success of the hip resection arthroplasty as a definitive surgery using a Kaplan-Meier curve. Results: Seven cases (26.9%) required a re-operation after the hip resection arthroplasty, four cases for persistent hip infection, and in the three remaining a conversion to a total hip arthroplasty was re-considered due to a good medical evolution and non-tolerance to the low functional outcome. The mortality rate was 61.5% (27 days-20 years), with a 19.2% mortality rate in the first 5 years. All the cases that required another surgery after the hip resection arthroplasty were re-operated within the first 18 months. Conclusion: Unfortunately, hip resection arthroplasty continues to show elevated re-operation rate and early mortality rate, as well as low functional outcomes. Two-staged hip revision arthroplasty is the surgical treatment of choice in patients suffering from a periprosthetic joint infection, however we believe that hip resection arthroplasty should be considered in fragile patients, who have endured multiple revision surgeries, or their comorbidities make them unfit from further surgeries.

COLONOMICS - integrative omics data of one hundred paired normal-tumoral samples from colon cancer patients.

Colonomics is a multi-omics dataset that includes 250 samples: 50 samples from healthy colon mucosa donors and 100 paired samples from colon cancer patients (tumor/adjacent). From these samples, Colonomics project includes data from genotyping, DNA methylation, gene expression, whole exome sequencing and micro-RNAs (miRNAs) expression. It also includes data from copy number variation (CNV) from tumoral samples. In addition, clinical data from all these samples is available. The aims of the project were to explore and integrate these datasets to describe colon cancer at molecular level and to compare normal and tumoral tissues. Also, to improve screening by finding biomarkers for the diagnosis and prognosis of colon cancer. This project has its own website including four browsers allowing users to explore Colonomics datasets. Since generated data could be reuse for the scientific community for exploratory or validation purposes, here we describe omics datasets included in the Colonomics project as well as results from multi-omics layers integration.

Is elective surgery during the COVID-19 pandemic safe? A multi-center prospective study in a high incidence area.

OBJECTIVE: The aim of this study was to describe the evolution of patients admitted for elective orthopaedic surgery during the immediate post-COVID-19 peak of the pandemic. METHODS: This is a multi-center, observational study conducted in 8 high complexity hospitals of Catalonia, one of the highest COVID-19 incidence areas in Spain. We included patients ≥18 years of age undergoing elective surgery (total knee or hip arthroplasty, knee or hip revision arthroplasty, shoulder or knee arthroscopy, hand or wrist surgery, forefoot surgery, or hardware removal) after the COVID-19 peak (between May 5th and June 30th, 2020). The main exclusion criterion was a positive result for SARS-CoV-2 PCR within the 7 days before the surgery. The primary outcomes were postoperative complications within 60 days (+/-30) or hospital readmission due to a COVID-19 infection. Following the recommendations of the International Consensus Group (ICM), elective surgeries were re-started when the nationwide lockdown was lifted. Before the surgery, patients were contacted by phone to rule out any exposure to confirmed COVID-19 cases, a reverse transcription-polymerase chain reaction (PCR) assay was performed in all patients 48-72 hours before hospital admission, and they were asked to maintain home confinement until the day of the surgery. RESULTS: 675 patients were included: 189 patients in the arthroplasty group (28%) and 486 in the ambulatory surgery group (72%). Mean [SD] age was 57.6 [15.3] years. The mean Charlson Comorbidity Index score was 2.21 (SD = 2.01, Min = 0, Max = 13). A total of 84 patients (12.75%) obtained an American Society of Anesthesiologists (ASA) score ≥ 3, showing no association between the ASA score and the risk of developing COVID-19 symptoms at follow-up (χ 2 (4) = 0.77, P = 0.94). The mean occupation rate of hospital beds for COVID-19 patients was 13% and the mean occupation rate of critical care beds for COVID-19 patients was 27% at the time of re-introducing elective surgeries. These were important rates to consider to decide when to reintroduce elective surgeries after lockdown. Surgical time, time of ischemia and intra-operative bleeding were not related with a higher risk of developing COVID-19 post-operatively (χ 2 (1) = 0.00, P = 0.98); (χ 2 (2) = 2.05, P = 0.36); (χ 2 (2) = 0.37, P = 0.83). Only 2 patients (0.3 %) presented with a suspected COVID-19 infection at follow-up. None of them presented with pneumonia or required confirmation by a reverse transcription PCR assay. Hospital re-admission was not needed for these patients. CONCLUSION: The risk of developing COVID-19 during the immediate post-COVID-19 peak in a region with a high incidence of COVID-19 has not been proved. These data suggest that elective orthopaedic surgeries can be resumed when assertive and strict protocols are followed.

The BRCA1 Pseudogene Negatively Regulates Antitumor Responses through Inhibition of Innate Immune Defense Mechanisms.

Innate immune defense mechanisms play a pivotal role in antitumor responses. Recent evidence suggests that antiviral innate immunity is regulated not only by exogenous non-self-RNA but also by host-derived pseudogene RNAs. A growing body of evidence also indicates a biological role for pseudogenes as gene expression regulators or immune modulators. Here, we report an important role for BRCA1P1, the pseudogene of the BRCA1 tumor-suppressor gene, in regulating innate immune defense mechanisms in breast cancer cells. BRCA1P1 expresses a long-noncoding RNA (lncRNA) in breast cancer cells through divergent transcription. Expression of lncRNA-BRCA1P1 is increased in breast tumors compared with normal breast tissues. Depletion of BRCA1P1 induces an antiviral defense-like program, including the expression of antiviral genes in breast cancer cells. Furthermore, BRCA1P1-deficient cancer cells mimic virus-infected cells by stimulating cytokines and inducing cell apoptosis. Accordingly, depletion of BRCA1P1 increases host innate immune responses and restricts virus replication. In converse, overexpression of BRCA1P1 reduces cytokine expression in breast cancer cells. Mechanistically, lncRNA-BRCA1P1 is localized in the nucleus, binds to the NF-κB subunit RelA, and negatively regulates antiviral gene expression. Finally, in a xenograft mouse model of breast cancer, depletion of BRCA1P1 stimulates cytokine expression and local immunity, and suppresses tumor growth. Our results suggest an important role for BRCA1P1 in innate immune defense mechanisms and antitumor responses. This mechanism of antiviral immunity regulated by a host-derived pseudogene RNA may guide the development of novel therapies targeting immune responses in breast cancer. SIGNIFICANCE: This study identifies a novel mechanism of innate immunity driven by a host pseudogene RNA that inhibits innate immune defense mechanisms and antitumor responses through regulation of antiviral gene expression.

DNA methylation events in transcription factors and gene expression changes in colon cancer.

Aim: Gain insight about the role of DNA methylation in the malignant growth of colon cancer. Patients & methods: Methylation and gene expression from 90 adjacent-tumor paired tissues and 48 healthy tissues were analyzed. Tumor genes whose change in expression was explained by changes in methylation were identified using linear models adjusted for tumor stromal content. Results: No differences in methylation were found between adjacent and healthy tissues, but clear differences were found between adjacent and tumor samples. We identified hypermethylated CpG islands located in promoter regions that drive differential gene expression of transcription factors and their target genes. Conclusion: Changes in methylation of a few genes provoke important changes in gene expression, by expanding the signal through transcription activation/repression.

Mortality Rates of Patients with Proximal Femoral Fracture in a Worldwide Pandemic: Preliminary Results of the Spanish HIP-COVID Observational Study.

BACKGROUND: The outbreak of coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), in December 2019 in Wuhan, People's Republic of China, has developed into an unprecedented pandemic with enormous pressure on health-care providers around the world. A higher mortality rate has been described in older infected individuals. Patients with hip fracture are a particularly vulnerable population during this pandemic because older age is associated with a higher mortality rate. Our aim was to describe the early mortality rate and demographic variables in a hip fracture sample population in Spain during the coronavirus pandemic. METHODS: This is a multicenter, observational, retrospective, descriptive study. We collected data from 13 major hospitals in Spain from the beginning of the national state of alarm (declared on March 14, 2020, by the Spanish government) until the end of our study period on April 4, 2020. All patients who were ≥65 years of age, presented to the Emergency Department of the participating hospitals during this period with a diagnosis of proximal femoral fracture, and had a minimum follow-up of 10 days were included in the cohort. In addition to mortality, demographic and other potential prognostic variables were also collected. RESULTS: In this study, 136 patients with a hip fracture were included. Of these patients, 124 underwent a surgical procedure and 12 were managed nonoperatively. The total mortality rate was 9.6%. Sixty-two patients were tested for COVID-19, with 23 patients being positive. The mortality rate for these 23 patients was 30.4% (7 of 23 patients) at a mean follow-up of 14 days. The mortality rate was 10.3% (4 of 39) for patients who had been tested and had a negative result and 2.7% (2 of 74) for patients who had not been tested. Of the 12 patients who were managed nonoperatively, 8 (67%) died, whereas, of the 124 patients who were surgically treated, 5 (4%) died. Results differed among centers. CONCLUSIONS: There is a higher mortality rate in patients with a hip fracture and an associated positive test for COVID-19. LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

The GATA3 X308_Splice breast cancer mutation is a hormone context-dependent oncogenic driver.

As the catalog of oncogenic driver mutations is expanding, it becomes clear that alterations in a given gene might have different functions and should not be lumped into one class. The transcription factor GATA3 is a paradigm of this. We investigated the functions of the most common GATA3 mutation (X308_Splice) and five additional mutations, which converge into a neoprotein that we called "neoGATA3," associated with excellent prognosis in patients. Analysis of available molecular data from >3000 breast cancer patients revealed a dysregulation of the ER-dependent transcriptional response in tumors carrying neoGATA3-generating mutations. Mechanistic studies in vitro showed that neoGATA3 interferes with the transcriptional programs controlled by estrogen and progesterone receptors, without fully abrogating them. ChIP-Seq analysis indicated that ER binding is reduced in neoGATA3-expressing cells, especially at distal regions, suggesting that neoGATA3 interferes with the fine tuning of ER-dependent gene expression. This has opposite outputs in distinct hormonal context, having pro- or anti-proliferative effects, depending on the estrogen/progesterone ratio. Our data call for functional analyses of putative cancer drivers to guide clinical application.

Neuropatía periférica producida por taxanos y calidad de vida global en pacientes con cáncer de mama / Peripheral neuropathy caused by taxanes and overall quality of life in breast cancer patients

OBJETIVO: determinar la incidencia y evolución de la neuropatía periférica inducida por taxanos (NPIT) en pacientes con cáncer de mama y valorar la influencia de la NPIT en la calidad de vida global (CV). MÉTODO: estudio descriptivo longitudinal prospectivo realizado en el Servicio de Oncología del Hospital Clínic de Barcelona (julio 2015-abril 2016). Se incluyeron mujeres diagnosticadas de cáncer de mama en su primera línea de tratamiento con quimioterapia (paclitaxel o docetaxel) en quienes se evaluó la neurotoxicidad y la calidad de vida mediante tres cuestionarios autoinformados validados al inicio, a las 6 y 12 semanas y un mes tras finalizar el tratamiento. RESULTADOS: participaron 33 pacientes de las cuales el 84,4% había desarrollado algún grado de NP al final del seguimiento. La neurotoxicidad empeoró de manera estadísticamente significativa con la acumulación de dosis hasta el final del tratamiento y se mantuvo estable un mes tras la última administración (p< 0,001). La neuropatía sensitiva aumentó de manera estadísticamente significativa a lo largo del seguimiento (p< 0,001). La afectación de la sensibilidad motora también, salvo en la última medición (p< 0,005). Se observó una correlación positiva entre la neurotoxicidad y deterioro de la CV (r= 0,609 (p< 0,0001)) CONCLUSIONES: la NPIT es un efecto secundario con una alta incidencia en la población de mujeres con cáncer de mama estudiada y provoca un efecto negativo en la CV percibida de las pacientes. Las enfermeras oncológicas son profesionales clave en la prevención y el manejo de este efecto secundario

OBJECTIVE: to determine the incidence and evolution of taxane-induced peripheral neuropathy (TIPN) in breast cancer patients, and to assess the influence of TIPN on overall quality of life (QoL). METHOD: a prospective longitudinal descriptive study conducted at the Oncology Unit of the Hospital Clínic de Barcelona (July, 2015- April, 2016). The study included women with diagnosis of breast cancer, on their first line of treatment with chemotherapy (paclitaxel or docetaxel); neurotoxicity and quality of life were evaluated through three self-reported questionnaires validated at baseline, at 6 and 12 weeks, and one month after completing treatment. RESULTS: the study included 33 patients; 84.4% of them had developed some degree of PN at the end of follow-up. There was a statistically significant worsening in neurotoxicity with dose accumulation until the end of the treatment, and it remained stable one month after the last administration (p< 0.001). There was a statistically significant increase in sensitive neuropathy throughout follow-up (p< 0.001); also in terms of involvement in motor sensitivity, except in the final measurement (p< 0-005). A positive correlation was observed between neurotoxicity and QoL deterioration (r= 0.609 (p < 0.0001)). CONCLUSIONS: TIPN is a side effect with high incidence among the population studied of women with breast cancer, and it causes a negative impact on patient-perceived QoL. Oncology nurses are the key professionals for the prevention and management of this side effect

Functional FLT1 Genetic Variation is a Prognostic Factor for Recurrence in Stage I-III Non-Small-Cell Lung Cancer.

BACKGROUND: We propose that single-nucleotide polymorphisms (SNPs) in genes of the vascular endothelial growth factor pathway of angiogenesis will associate with survival in non-small-cell lung cancer (NSCLC) patients. METHODS: Fifty-three SNPs in vascular endothelial growth factor-pathway genes were genotyped in 150 European stage I-III NSCLC patients and tested for associations with patient survival. Replication was performed in an independent cohort of 142 European stage I-III patients. Reporter gene assays were used to assess the effects of SNPs on transcriptional activity. RESULTS: In the initial cohort, five SNPs associated (q < 0.05) with relapse-free survival (RFS). The minor alleles of intronic FLT1 SNPs, rs7996030 and rs9582036, associated with reduced RFS (hazard ratio [HR] = 1.67 [95% confidence interval, CI, 1.22-2.29] and HR = 1.51 [95% CI, 1.14-2.01], respectively) and reduced transcriptional activity. The minor alleles of intronic KRAS SNPs, rs12813551 and rs10505980, associated with increased RFS (HR = 0.64 [0.46-0.87] and HR = 0.64 [0.47-0.87], respectively), and the minor allelic variant of rs12813551 also reduced transcriptional activity. Lastly, the minor allele of the intronic KRAS SNP rs10842513 associated with reduced RFS (HR = 1.65 [95% CI, 1.16-2.37]). Analysis of the functional variants suggests they are located in transcriptional enhancer elements. The negative effect of rs9582036 on RFS was confirmed in the replication cohort (HR = 1.69 [0.99-2.89], p = 0.028), and the association was significant in pooled analysis of both cohorts (HR = 1.67 [1.21-2.30], p = 0.0001). CONCLUSIONS: The functional FLT1 variant rs9582036 is a prognostic determinant of recurrence in stage I-III NSCLC. Its predictive value should be tested in the adjuvant setting of stage I-III NSCLC.

Exome Sequencing Reveals AMER1 as a Frequently Mutated Gene in Colorectal Cancer.

PURPOSE: Somatic mutations occur at early stages of adenoma and accumulate throughout colorectal cancer progression. The aim of this study was to characterize the mutational landscape of stage II tumors and to search for novel recurrent mutations likely implicated in colorectal cancer tumorigenesis. EXPERIMENTAL DESIGN: The exomic DNA of 42 stage II, microsatellite-stable colon tumors and their paired mucosae were sequenced. Other molecular data available in the discovery dataset [gene expression, methylation, and copy number variations (CNV)] were used to further characterize these tumors. Additional datasets comprising 553 colorectal cancer samples were used to validate the discovered mutations. RESULTS: As a result, 4,886 somatic single-nucleotide variants (SNV) were found. Almost all SNVs were private changes, with few mutations shared by more than one tumor, thus revealing tumor-specific mutational landscapes. Nevertheless, these diverse mutations converged into common cellular pathways, such as cell cycle or apoptosis. Among this mutational heterogeneity, variants resulting in early stop codons in the AMER1 (also known as FAM123B or WTX) gene emerged as recurrent mutations in colorectal cancer. Losses of AMER1 by other mechanisms apart from mutations such as methylation and copy number aberrations were also found. Tumors lacking this tumor suppressor gene exhibited a mesenchymal phenotype characterized by inhibition of the canonical Wnt pathway. CONCLUSIONS: In silico and experimental validation in independent datasets confirmed the existence of functional mutations in AMER1 in approximately 10% of analyzed colorectal cancer tumors. Moreover, these tumors exhibited a characteristic phenotype.

Large differences in global transcriptional regulatory programs of normal and tumor colon cells.

BACKGROUND: Dysregulation of transcriptional programs leads to cell malfunctioning and can have an impact in cancer development. Our study aims to characterize global differences between transcriptional regulatory programs of normal and tumor cells of the colon. METHODS: Affymetrix Human Genome U219 expression arrays were used to assess gene expression in 100 samples of colon tumor and their paired adjacent normal mucosa. Transcriptional networks were reconstructed using ARACNe algorithm using 1,000 bootstrap replicates consolidated into a consensus network. Networks were compared regarding topology parameters and identified well-connected clusters. Functional enrichment was performed with SIGORA method. ENCODE ChIP-Seq data curated in the hmChIP database was used for in silico validation of the most prominent transcription factors. RESULTS: The normal network contained 1,177 transcription factors, 5,466 target genes and 61,226 transcriptional interactions. A large loss of transcriptional interactions in the tumor network was observed (11,585; 81% reduction), which also contained fewer transcription factors (621; 47% reduction) and target genes (2,190; 60% reduction) than the normal network. Gene silencing was not a main determinant of this loss of regulatory activity, since the average gene expression was essentially conserved. Also, 91 transcription factors increased their connectivity in the tumor network. These genes revealed a tumor-specific emergent transcriptional regulatory program with significant functional enrichment related to colorectal cancer pathway. In addition, the analysis of clusters again identified subnetworks in the tumors enriched for cancer related pathways (immune response, Wnt signaling, DNA replication, cell adherence, apoptosis, DNA repair, among others). Also multiple metabolism pathways show differential clustering between the tumor and normal network. CONCLUSIONS: These findings will allow a better understanding of the transcriptional regulatory programs altered in colon cancer and could be an invaluable methodology to identify potential hubs with a relevant role in the field of cancer diagnosis, prognosis and therapy.

Identification of candidate susceptibility genes for colorectal cancer through eQTL analysis.

In this study, we aim to identify the genes responsible for colorectal cancer risk behind the loci identified in genome-wide association studies (GWAS). These genes may be candidate targets for developing new strategies for prevention or therapy. We analyzed the association of genotypes for 26 GWAS single nucleotide polymorphisms (SNPs) with the expression of genes within a 2 Mb region (cis-eQTLs). Affymetrix Human Genome U219 expression arrays were used to assess gene expression in two series of samples, one of healthy colonic mucosa (n = 47) and other of normal mucosa adjacent to colon cancer (n = 97, total 144). Paired tumor tissues (n = 97) were also analyzed but did not provide additional findings. Partial Pearson correlation (r), adjusted for sample type, was used for the analysis. We have found Bonferroni-significant cis-eQTLs in three loci: rs3802842 in 11q23.1 associated to C11orf53, COLCA1 (C11orf92) and COLCA2 (C11orf93; r = 0.60); rs7136702 in 12q13.12 associated to DIP2B (r = 0.63) and rs5934683 in Xp22.3 associated to SHROOM2 and GPR143 (r = 0.47). For loci in chromosomes 11 and 12, we have found other SNPs in linkage disequilibrium that are more strongly associated with the expression of the identified genes and are better functional candidates: rs7130173 for 11q23.1 (r = 0.66) and rs61927768 for 12q13.12 (r = 0.86). These SNPs are located in DNA regions that may harbor enhancers or transcription factor binding sites. The analysis of trans-eQTLs has identified additional genes in these loci that may have common regulatory mechanisms as shown by the analysis of protein-protein interaction networks.

Aberrant gene expression in mucosa adjacent to tumor reveals a molecular crosstalk in colon cancer.

BACKGROUND: A colorectal tumor is not an isolated entity growing in a restricted location of the body. The patient's gut environment constitutes the framework where the tumor evolves and this relationship promotes and includes a complex and tight correlation of the tumor with inflammation, blood vessels formation, nutrition, and gut microbiome composition. The tumor influence in the environment could both promote an anti-tumor or a pro-tumor response. METHODS: A set of 98 paired adjacent mucosa and tumor tissues from colorectal cancer (CRC) patients and 50 colon mucosa from healthy donors (246 samples in total) were included in this work. RNA extracted from each sample was hybridized in Affymetrix chips Human Genome U219. Functional relationships between genes were inferred by means of systems biology using both transcriptional regulation networks (ARACNe algorithm) and protein-protein interaction networks (BIANA software). RESULTS: Here we report a transcriptomic analysis revealing a number of genes activated in adjacent mucosa from CRC patients, not activated in mucosa from healthy donors. A functional analysis of these genes suggested that this active reaction of the adjacent mucosa was related to the presence of the tumor. Transcriptional and protein-interaction networks were used to further elucidate this response of normal gut in front of the tumor, revealing a crosstalk between proteins secreted by the tumor and receptors activated in the adjacent colon tissue; and vice versa. Remarkably, Slit family of proteins activated ROBO receptors in tumor whereas tumor-secreted proteins transduced a cellular signal finally activating AP-1 in adjacent tissue. CONCLUSIONS: The systems-level approach provides new insights into the micro-ecology of colorectal tumorogenesis. Disrupting this intricate molecular network of cell-cell communication and pro-inflammatory microenvironment could be a therapeutic target in CRC patients.

Discovery and functional assessment of gene variants in the vascular endothelial growth factor pathway.

Angiogenesis is a host-mediated mechanism in disease pathophysiology. The vascular endothelial growth factor (VEGF) pathway is a major determinant of angiogenesis, and a comprehensive annotation of the functional variation in this pathway is essential to understand the genetic basis of angiogenesis-related diseases. We assessed the allelic heterogeneity of gene expression, population specificity of cis expression quantitative trait loci (eQTLs), and eQTL function in luciferase assays in CEU and Yoruba people of Ibadan, Nigeria (YRI) HapMap lymphoblastoid cell lines in 23 resequenced genes. Among 356 cis-eQTLs, 155 and 174 were unique to CEU and YRI, respectively, and 27 were shared between CEU and YRI. Two cis-eQTLs provided mechanistic evidence for two genome-wide association study findings. Five eQTLs were tested for function in luciferase assays and the effect of two KRAS variants was concordant with the eQTL effect. Two eQTLs found in each of PRKCE, PIK3C2A, and MAP2K6 could predict 44%, 37%, and 45% of the variance in gene expression, respectively. This is the first analysis focusing on the pattern of functional genetic variation of the VEGF pathway genes in CEU and YRI populations and providing mechanistic evidence for genetic association studies of diseases for which angiogenesis plays a pathophysiologic role.