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Proteasomal degradation is an essential regulatory mechanism for cellular homeostasis maintenance. The speckle-type POZ adaptor protein (SPOP) is part of the ubiquitin ligase E3 cullin-3 RING-box1 complex, responsible for the ubiquitination and proteasomal degradation of biomolecules involved in cell cycle control, proliferation, response to DNA damage, epigenetic control, and hormone signaling, among others. Changes in SPOP have been associated with the development of different types of cancer, since it can act as a tumor suppressor mainly in prostate, breast, colorectal, lung cancer and liver cancer, due to point mutations and/or reduced expression, or as an oncogene in endometrial cancer, in which function gain has been found, and in kidney cancer by protein overexpression. SPOP is a potential prognostic biomarker and a promising therapeutic target.

Las alteraciones en la metilación de dinucleótidos CpG en regiones promotoras es uno de los mecanismos epigenéticos implicados en cáncer que tiene uso potencial como biomarcador. Su evaluación a partir de tejidos fijados en formalina y embebidos en parafina (FFPE) representa un gran desafío dadas la degradación parcial, el entrecruzamiento y las bajas cantidades del DNA obtenido. En esta nota técnica describimos un protocolo para el estudio del estado de metilación del promotor distal del proto-oncogén K-RAS a partir de varias muestras obtenidas de dos tejidos FFPE de cáncer colorrectal con antigüedad de 11 años. Se empleó un protocolo de conversión con bisulfito alternativo al usual; se usó una DNA polimerasa modificada y una PCR anidada y se optimizó la secuenciación directa del DNA convertido con bisulfito. Este protocolo podría ser aplicado para determinar estados de metilación en otros genes y tipos de cáncer en tejidos FFPE.

Resumen El tratamiento para cancer de prostata localizado (prostatectomia radical o radioterapia) ofrece unas altas tasas de curacion; sin embargo, del 20 al 30% de los casos desarrollan recurrencia bioquimica. Actualmente, existen factores clinicos y patologicos que ayudan a predecir recurrencia; no obstante tanto el caracter heterogeneo de estos tumores, las diferencias en los tiempos de progresion de cancer localizado a metastasico como la resistencia al tratamiento han dado lugar a imprecisiones en la prediccion del pronostico y a tratamientos insuficientes o excesivos. Debido a esto se han estudiado biomarcadores con el fin de estratificar mas acertadamente el riesgo y mejorar las decisiones de tratamiento de una manera adecuada y oportuna. Este manuscrito presenta una revision de marcadores moleculares de pronostico que se han propuesto en los pacientes con cancer de prostata localizado, lo que podria permitir establecer con mayor precision el riesgo de recurrencia de la enfermedad.

Introduction: Colorectal cancer (CRC) has the third-highest incidence and the fourth-highest mortality from cancer globally. In the genesis of CRC, mutations have been identified in the KRAS gene associated with prognosis and therapeutic management, however, the epigenetic mechanisms that modulate the expression of KRAS in CRC patients when there are no mutations in the gene are not well known. miR-18a-3p and miR-143 have been described to target KRAS and thus may regulate gene expression. Objective: To determine if there is a relationship between the expression of the wild-type KRAS gene (mRNA and protein) and the expression levels of miR-143 and miR-18a-3p in FFPE tissue samples from CRC patients. Methodology: RNA was extracted from FFPE tumor tissue samples from 51 cases of patients with CRC. Expression of wild-type KRAS mRNA, miR-143 and miR-18a-3p was evaluated by qRT-PCR and expression levels of KRAS protein by immunohistochemistry. Contingency tables, Pearson's Chi-square test and logistic regression analysis were used for data analysis. Results: Regarding the expression levels of wild-type KRAS protein, a higher number of cases with a cytoplasmic expression of the protein was identified (98%) compared to the expression in the cell membrane (31%). In 7,8% (4/51) of the cases, it was not possible to determine the mRNA expression of the KRAS gene, while in 21,3% (10/47) no expression was detected. In 78,7% of the cases in which KRAS mRNA expression was detected, low (40,4%; 19/47) and high (38,3%; 18/47) expression were categorized according to the results found. It was not evidenced by a correlation between protein expression levels and mRNA expression levels of the wild-type KRAS gene. When determining the expression levels of miR-18a-3p and miR-143, it was found that 64,7% (33/51) of cases had an absent expression of miR-18a-3p and 54,9% (28/51) of cases had an absent or very low expression for miR-143. By means of a logistic regression analysis adjusted by age, stage, sex and presence or absence of KRAS protein in the membrane, it was determined that the presence of miR-18a-3p is inversely related to KRAS mRNA levels significantly (p=0,048; OR=0,346) while miR-143 only shows a tendency to an inverse correlation with KRAS mRNA levels (p=0,119; OR=0,469). Conclusions: No correlation was found between mRNA and protein expression levels of the wild-type KRAS gene, suggesting that protein levels do not strictly depend on mRNA levels. A significant inverse association was found between miR-18a-3p and wild-type KRAS mRNA levels. Citation Format: Jehison-Alirio Herrera-Pulido, Orlando Ricaurte Guerrero, Jinneth Acosta Forero, Gustavo Hernández Suárez, Pablo Moreno-Acosta, María-Carolina Sanabria Salas, Humberto Arboleda Granados, Alfredo Romero Rojas, Martha Lucía Serrano López. Association between miR-18a-3p, miR-143 and expression of the wild-type KRAS gene in patients with sporadic colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2130.

Prostate cancer (PCa) is the type of cancer with the highest incidence and mortality in our country. Current disease prognostic factors do not differentiate aggressive from indolent cases with sufficient certainty and for this reason, it has worked on a characterization of molecular subtypes that allows for a better classification. In localized PCa, fusions between the gene regulated by androgens TMPRSS2 and ERG, or mutations in SPOP (speckle type POZ, the gene that codes for an adapter protein of the Cullin-3-RING-Box1 complex) have been detected in different populations, which has been related to prognosis; however, we do not know the relevance of these molecular alterations in affected Colombians. These two alterations are described within the 7 subtypes reported by the TCGA and are considered mutually exclusive. Objective: Evaluate the presence of ERG and SPOP subtypes in prostate cancer in the Colombian population and correlate these findings with clinicopathological parameters. Methodology: For this study, FFPE radical prostatectomy samples from 112 patients with PCa were used, where the TMPRSS2-ERG fusions were studied by FISH, and in negative cases for fusion, mutations in exons 6 and 7 of SPOP were evaluated by sanger sequencing. Results: Fusion was detected in 71 patients (63.4%), this frequency of the ERG subtype was similar to that observed in the Caucasian population (40-60%). No statistically significant differences were found between the fusion state and the clinicopathological variables analyzed such as age, initial PSA, Gleason score, Gleason grade group, clinical and pathological tumor stage, lymph node involvement, biochemical recurrence-free survival, and overall survival. In the 41 (36.6%) cases negative for fusion, only one mutation (F133L) was detected in exon 7, which has previously been reported in 34 cases. Conclusions: The frequency of fusion of the ERG subtype detected in our population was 63.4%, no associations were found between the fusion state and the prognosis of the disease. Until now, 1 case has been detected a mutation of exon 7 of SPOP (2.4%). The low frequency of this subtype in Colombians could be explained by the reported variability in the frequency of these mutations according to the population (5% -20%). Citation Format: Wendy Montero Ovalle, Yenifer Segura Moreno, María Carolina Sanabria-Salas, Jorge Mesa López de Mesa, Rodolfo Varela Ramírez, Vilma Medina Boada, Martha Lucía Serrano López. Analysis of ERG and SPOP subtypes in prostate cancer in the Colombian population and their possible implications on prognosis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 760.

Background: DNA methylation plays an important role in colorectal cancer (CRC) carcinogenesis. The mutated K-RAS gene has been reported to be crucial in CRC progression, but it is not known whether the wild-type gene is regulated by methylation and whether or not this mechanism contributes to disease progression. Now, there are not known reports about the methylation status of the distal K-RAS gene promoter in patients diagnosed with CRC. Materials and methods: Fifty-seven formalin-fixed, paraffin-embedded (FFPE) tissue samples from 57 patients diagnosed with CRC, without K-RAS mutation, were analyzed to determine the methylation status of the distal promoter of this gene. The analysis was performed by DNA extraction from laser microdissections, and 2 mm diameter punch, conversion with sodium bisulfite, amplification by nested PCR, and direct sequencing of purified PCR products. Results: Of the 57 cases, in 2 (6.25%) partial methylation was found in island 2 for one of the cases and in islands 1 and 2 for the other. In 30 (93.75%) cases no methylation was found and in the remaining 25 (43.85%) cases methylation could not be determined, probably due to the quantity and quality of DNA extracted from these blocks. Conclusion: The results found from the preliminary analysis of the methylation status of a region of the distal promoter of the K-RAS gene that serves as an anchorage to Sp1, allowed to determine a partial methylation status in 6.25% of the cases studied, concluding that methylation in this region is not a frequent event Citation Format: Jehison Alirio Herrera-Pulido, Orlando Ricaurte-Guerrero, Jinneth Acosta-Forero, Pablo Moreno-Acosta, María Carolina Sanabria-Salas, Humberto Arboleda-Granados, Gustavo Hernández, Martha Lucía Serrano-López. DNA methylation status in a promoter region of the K-RAS gene in patients with Colorectal Cancer [abstract]. In: Abstracts: AACR Special Virtual Conference on Epigenetics and Metabolism; October 15-16, 2020; 2020 Oct 15-16. Philadelphia (PA): AACR; Cancer Res 2020;80(23 Suppl):Abstract nr PO-019.

Hereditary breast cancer (BC) syndromes corresponds to 10% - 15% of all cases diagnosed worldwide. Most of these cases are due to deleterious germline genetic variants in BRCA1/2 genes; nevertheless, multipanel testing have contribute to the identification of other risk genes, including other homologous recombination (HR) repair genes, such as PALB2, ATM, CHEK2 and RAD51D. Here we explore the mutation spectrum of Hereditary Breast and Ovarian Cancer (HBOC) Colombian cases as part of the Hereditary Cancer Program from the National Cancer Institute from Colombia, the largest reference cancer center in the country, that seeks to identified high risk families to offer preventive measures and screening recommendations. A total of 358 patients fulfilling criteria for HBOC have been so far analyzed with Next Generation Sequencing using a multigene panel. Overall, 47% have negative results and in the 33% we identified VUSs. In general, 20% have a pathogenic or potentially pathogenic genetic variant; from those, BRCA1 (n = 17) and BRCA2 (n = 17) were the most frequently mutated genes (47.2% among all positive results). Deleterious mutations in RAD51D and PALB2 (also important HR repair genes) were found in 7% and 5.6% of the cases tested. Interestingly, genotype:phenotype correlations were found for these genes, as breast cancer molecular subtypes were distributed differently depending on the gene affected. In concordance with other reports, triple negative breast cancers (TNBC) were more frequent in BRCA1 (9/17, 53%) and PALB2 (4/4, 100%) carriers, and luminal subtypes were more frequent in BRCA2 carriers (10/17, 59%). Mutations in RAD51D: c.94_95del (p.Val32Phefs*67) and PALB2: c.2288_2291del (p.Leu763Ter), were both recurrent mutations in our Colombian cases. Further haplotype analysis will help us to determine if mutation carriers shared a common ancestry. Citation Format: Maria Carolina Sanabria-Salas, Ana Lucía Rivera-Herrera, Ana Milena Gómez-Camargo, Luis G. Carvajal-Carmona, Martha Lucía Serrano-López. Recurrent germline mutations in RAD51D and PALB2 are present in Colombian hereditary breast and ovarian cancer families [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1211.

Introduction: Colorectal cancer (CRC) is one of the most common cancers worldwide, with higher incidence among more developed countries. However, mortality rates are higher and increasing in less-developed regions, including Colombia. Incidence and mortality rates of CRC vary across the country, with the lowest rates among populations with increased concentration of Native Americans. Our group previously reported that increased European and African ancestry was associated with higher adenomatous polyps (AP) and CRC risk in Colombians. Based on this observation we hypothesize that genetic contribution to the observed regional variation on CRC development in Colombia might be partly explained by the influence of genetic variants with different frequency distribution in the European, Amerindian, and African ancestral components. Objective: To test our hypothesis we performed a genome-wide association study (GWAS) of colorectal tumors in Colombian CRC and AP cases and controls. Materials and Methods: We conducted a GWAS of Colombians from different regions of the country that included 162 CRC cases, 122 AP cases, and 131 controls. Only SNPs with MAF ≥ 0.05 were included. The role of these common variants was assessed by logistic regression models adjusted for age, sex, and the first 10 principal components (PCs) of the genetic variation. Analyses were performed for a total of 606410 SNPs. The P value threshold for genome-wide significant SNPs was set at the traditional value of ≤ 5 × 10−8. Results: We replicated some of the previously reported associations (8 out of 44 SNPs, P ≤ 0.05) of which 7 had directionally concordant ORs. Regarding the remaining 36 published risk variants, 25 had directionally concordant ORs, even though neither of them was significant at nominal P ≤ 0.05. None of the SNPs analyzed passed the threshold for genome-wide significance. However, we found multiple suggestive associations. One novel SNP within the region 2q11.2-q12 near the gene MAP4K4 was associated with the risk of AP (rs4280476-G; OR 0.36; 95% CI 0.23-0.56; P = 8.7 x 10-6). We also found four novel SNPs across three regions with suggestive CRC risk associations: rs10514122-A located in the locus 5q14 near the TBCA gene (OR 0.30; 95% CI 0.18-0.49; P = 3.6 x 10-6), rs10746883-G (OR 0.37; 95% CI 0.25-0.56; P = 3.2 x 10-6) and the rs10781032-A (OR 0.35; 95% CI 0.22-0.53; P = 1.7 x 10-6), in high LD with each other (R2 = 0.81), located in the locus 9q21.1-q21.2 near the genes TRPM3 and TMEM2 and the SNP rs2800641-G located in the region 6q25.2 near the MYCT1 gene (OR 2.96; 95% CI 1.83-4.77; P = 8.9 x 10-6). The inflation factors (λ), when comparing AP or CRC cases vs controls, were 1.05 and 1.04, respectively, indicating appropriate control for population stratification. Finally, it is of note that the MAF reported for the 5 novel SNPs identified in our study shows important differences between European, Asian, and African reference populations from the public database 1,000 genomes. Conclusions: In this GWAS of AP and CRC in individuals from Colombia, we replicated some of the previously reported associations and identified suggestive signals for 5 novel risk alleles located at four loci (2q11.2-q12, 5q14, 9q21.1-q21.2, and 6q25.2). Further work is needed to replicate our findings in other Latin American populations. Citation Format: Maria Carolina Sanabria-Salas, Laura Fejerman, Konrad Rawlik, Albert Tenesa, Martha L. Serrano-Lopez, Jovanny Zabaleta, Gustavo A. Hernandez-Suarez. Genome-wide association study of colorectal tumors in Latin American individuals from Colombia [abstract]. In: Proceedings of the Tenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2017 Sep 25-28; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2018;27(7 Suppl):Abstract nr A37.

Introduction: Colorectal cancer (CRC) is the fourth leading cause of cancer death in Colombia, where mortality rates are increasing. Current screening and diagnosis methods range from non-invasive and not very sensitive and specific, such as occult blood in feces, to highly sensitive and specific but invasive, such as colonoscopy plus biopsy. Furthermore, the carcinoembryonic antigen in plasma, used as patient monitoring and prognostic biomarker, have a low specificity for the disease. Therefore, there is a need to find minimally invasive and accessible biomarkers that have potential as tools for screening, diagnosis or prognosis of CRC with a high sensitivity and specificity. Objective: To explore differences of plasma proteomic profiles between CRC cases and controls from Colombia, and to propose potential biomarkers of the disease. Materials and methods: We applied a bottom-up shotgun proteomics method to explore the plasma proteome profile of 20 CRC cases and 6 controls from Colombia, using RPLC coupled with an ESI-Q-Exactive Orbitrap. Mass spectra were collected in data-dependent mode with one MS precursor scan followed by 15 MS/MS scans. Mass spectra were analysed with X! Tandem, using the Uniprot Human Reference. 469 proteins were selected in Scaffold software after applying a Peptide and Protein Prophet scores of > 99% and > 95%, respectively, with a minimum of 2 peptides. Differential expression analyses were performed with the R package DESeq2 on the spectral count data, which uses a negative binomial GLM fitting and Wald statistics. Results: Using the first two principal components that explained 25% and 16% of the variance, led to separate most of the cases and controls of the study. We did not find significant differences in the only cases analyses (rectum vs. colon; left vs right; invasive vs in situ) after adjusting for multiple tests. When comparing CRC cases with controls we found 14 proteins differentially expressed (FDR < 0.05). Three of these proteins have a fold change of ± 2; LV401 and CD14 were found overexpressed in CRC cases whilst FBLN1 was found overexpressed in controls. Moreover, both supervised and unsupervised cluster analysis confirmed their utility as predictors of the disease. Conclusions: We identified a profile of 14 differentially expressed proteins among CRC cases compared to controls from Colombia. All these proteins have previously been found to be associated with CRC, or other cancer types, since they play an important role in the regulation or structure of the extracellular matrix, in the inflammatory response, in lipid metabolism and in drug resistance. Three of these are strong candidates as disease prognostic biomarkers (LV401, CD14 and FBLN1) according to what has been reported in the literature. Additional validation studies are required in a larger sample, including patients with CRC at different stages of the disease, in order to adequately assess their clinical utility. Citation Format: María Carolina Sanabria-Salas, Ruth Andrea Rodríguez-Castro, Martha Lucía Serrano-López, Gustavo Hernández-Suárez, Myriam Sánchez de Gómez, Adriana Umaña-Pérez. Differential plasma proteome analysis in patients with colorectal cancer from Colombia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr LB-072. doi:10.1158/1538-7445.AM2017-LB-072

Introduction: Around 63 common risk variants have been associated with colorectal cancer (CRC) through genome-wide association studies (GWAS) in European and Asian populations; these variants, together with the high penetrance genes responsible for 5% of the cases, do not completely explain the CRC heritability estimated at ~ 35%. Objective: To discover new common variants associated with the risk of colorectal tumors, taking advantage of the high level of admixture in Latino populations. Materials and methods: We performed a candidate gene association (CG) and GWAS analyses, in a multicenter case-control study that included 313 cases of CRC, 200 cases of adenomatous polyps (AP) and 506 controls from six Colombian cities. The role of these common variants was assessed by basic SNP association analyses (X2) and logistic regressions adjusted for age, sex and ancestry proportions. Selected SNPs were genotyped by TaqMan in additional samples. Results: European ancestry was associated with the risk of AP while African ancestry was associated with the risk of both, AP and CCR, (P ≤ 0.01). In the adjusted logistic regression analyses of the CG study, we found that the minor allele (A) of the SNP 14q11.2:rs1760898 (C>A) was associated with the risk of CRC (OR 0.48; 95% CI 0.33-0.69; UNADJ P = 6.8 x 10-5; 100,000 Pperm = 0.03). This association persisted in the adjusted logistic regressions analyses with additional samples genotyped by TaqMan (P = 0.03). In the basic SNP association analyses (X2) of the GWAS study, we found that the minor allele (A) of the SNP 17q25.3:rs1065768 (G>A) was associated with the risk of AP (OR 0.35; 95% CI 0.24 -0.51; UNADJ P = 3.4 x 10-8; Bonferroni corrected P = 0.02). This association persisted after including additional samples genotyped by TaqMan, both, in the basic SNP analysis (P = 1.7 x 10-7) and in the adjusted logistic regressions analysis (P = 9.7 x 10-5). Moreover, the association remained when other variables were also included in the model, such as the first 10 major principal components of genetic variability, ancestry proportions along chromosome 17 and locus-specific ancestry (P = 1.7 x 10-4). Conclusions: The SNP rs1760898 (TEP1, Telomerase Associated Protein 1 gene) confers a change of Asparagine (Asn) to Lysine (Lys) within the RNA binding domain, TROVE. This change could affect the activity of telomerase enzyme that has an important role in cancer development. The SNP rs1065768 (3'UTR TK1, Thymidine kinase 1 gene) could affect mRNA stability and protein production of TK1, which is essential in DNA synthesis. Although, functional analyses are required to confirm their potential role in colorectal tumorogenesis, our findings help increase our understanding about the biological basis for the development of colorectal tumors, as well as will contribute to the overall knowledge on the heritability of CRC. Citation Format: María Carolina Sanabria-Salas, Konrad Rawlik, Albert Tenesa, Adriana Umaña-Pérez, Martha Lucía Serrano-López, Myriam Sánchez de Gómez, Jovanny Zabaleta, Gustavo Hernández-Suárez. Common genetic variants within TEP1 gene (14q11.2 locus) and TK1 gene (17q25.3 locus) are associated with the risk of colorectal tumors in Latinos [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr LB-162. doi:10.1158/1538-7445.AM2017-LB-162

En la actualidad no existe una herramienta que permita diferenciar pacientes con cáncer de próstata (CaP) de mal pronóstico de aquellos con enfermedad indolente que sólo requieren un seguimiento controlado de la enfermedad. Debido a la coexistencia de diferentes focos premalignos y malignos en el CaP, el entendimiento sobre el proceso de carcinogénesis requiere de un mejor conocimiento. Actualmente, la heterogeneidad morfológica en CaP es evaluada con la puntuación de Gleason, la cual está fuertemente relacionada con el pronóstico de la enfermedad, sin embargo, esto es insuficiente por lo que se trabaja actualmente en identificación de alteraciones moleculares que permitan identificar subtipos que puedan establecer de manera más precisa el pronóstico del paciente. Este estudio preliminar buscó la estandarización del método de cuantificación en muestras prostáticas de FFPE de la expresión de los transcritos de posibles biomarcadores, como los oncogenes SPINK-1 y EZH2, el supresor tumoral NKX3.1, en conjunto con la determinación de la presencia/ausencia del gen de fusión TMPRSS2:ERG, ya que estos transcritos se encuentran involucrados en aparentes eventos excluyentes de la evolución natural del CaP, que apoyan la posibilidad de una clasificación molecular para esta enfermedad. At present doesn't exist tool to differentiate patients with prostate cancer (PCa) of poor prognosis of those with indolent disease that only require a controlled monitoring of the disease. Because of the coexistence of different premalignant and malignant foci in CaP, the understanding of the carcinogenesis process requires a better understanding. Currently, the morphological heterogeneity in PCa is evaluated with Gleason score, which is closely related to the prognosis of the disease, but this is insufficient so it is currently to work on identifying molecular alterations to identify subtypes that can establish more precisely the patient's prognosis. This preliminary study aimed to standardization of the method of quantification in prostatic samples of FFPE of expression of transcripts of possible biomarkers, such as the oncogenes, SPINK-1 y EZH2, the tumour suppressor, NKX3.1, together with the determination of the presence/absence of gene fusion, TMPRSS2:ERG, being that these transcripts are involved in apparent exclusive events of the natural evolution of PCa, that support the possibility of a molecular classification for this disease.

Introduccion Los polimorfismos de un solo nucleotido (SNPs) en citoquinas pueden afectar la expresion genica favoreciendo procesos de inflamacion y carcinogenesis. Hay resultados contradictorios con respecto a la asociacion entre marcadores en el gen de IL1B con cancer colorrectal (CCR). La mayoria de los reportes sobre esta asociacion han analizado el efecto de SNPs individuales. Sin embargo, existe evidencia sobre la importancia de estudiar el contexto haplotipico con el fin de entender mejor el efecto de estas variables en la expresion del gen y el CCR. Objetivo Evaluar la asociacion entre el CCR y polipos adenomatosos (PA) con haplotipos del gen de IL1B en poblaciones colombianas. Materiales y metodos Se reclutaron 317 CCR, 199 PA y 511 controles (pareados por edad y sexo) en 6 ciudades colombianas con diferente riesgo para CCR, como parte de un estudio multicentrico de casos y controles dirigido a la identificacion de factores de riesgo ambientales y geneticos para CCR en nuestro pais. Los participantes firmaron un consentimiento informado, donaron muestras de sangre y respondieron cuestionarios. Se genotiparon 5 SNPs del gen de IL1B (−3737, −1464, −511, −31 y +3954) mediante Taqman® SNP Genotyping Assays. Se calculo el equilibrio de Hardy-Weinberg (HWE) y se realizaron los analisis estadisticos usando regresion logistica condicional ajustando por factores de riesgo y ancestria. El desequilibrio de ligamiento (LD) fue calculado usando Haploview 4.0 mediante los estadisticos D′ y r2. Los analisis de haplotipos se realizaron en STATA v11.0 bajo un modelo aditivo. Este estudio fue aprobado por el Comite de Etica del Instituto Nacional de Cancerologia. Resultados Los controles se encontraron en HWE (p > 0,05). Encontramos un bloque haplotipico que incluyo los cuatro SNPs de la region promotora del gen de IL1B. Los SNPs IL1B-31 e IL1B-511 se encontraron en perfecto LD (D′: 0,998; r2: 0,948), es decir, que son TagSNPs. Bajo un modelo aditivo, encontramos una asociacion entre el haplotipo -3737C/-1464G/-511T/-31C y el riesgo de CCR (p Conclusiones Existe una asociacion positiva entre el haplotipo -3737C/-1464G/-511T/-31C y el riesgo de CCR en la poblacion colombiana.

Background: Colorectal cancer mortality rates are heterogeneous across Colombian territory and this variation could be explained by regional differences in Colombian ethnicity due to our high population admixture. Different frequencies of the interleukin 1 beta (IL1B) genetic variations have been described among diverse ethnical groups, but there are no reports on the possible association of these variants with colorectal cancer (CRC) risk as an effect of the genetic population dynamics in Colombia. Methods: To evaluate the association of IL1B haplotypes with colorectal carcinogenesis, we genotyped 317 CRC cases, 199 adenomatous polyps (AP) and 511 age-sex matched controls recruited from six Colombian cities located either on the coastal or the inner zone of the country. Five IL1B SNPs (-3737, -1464, -511, -31 and +3954) were genotyped and all were in HWE (p>0.05). We used data from previous analysis to estimate individual ancestral genetic fractions using STRUCTURE software based on allele frequencies of 678 autosomal SNPs cross-matched with the HapMap dataset, not in LD, and assuming three distinct population origins (CEU, LWJ and CHB populations) from HapMap project as references. Results: We found a 4-SNPs haplotype block (-3737C/-1464G/-511T/-31C) with high LD associated with CRC risk. Additional analysis revealed that this association persisted after adjusting by confounding variables including ancestry information (OR 1.95; CI 1.12 - 3.38; p =0.02). Interestingly, this association was evident among individuals from the coastal zone of the country and it was related with their higher African ancestry fraction (OR 2.26; 95%CI 1.22-4.18; p =0.01). Our results are in agreement with previous reports showing that this haplotype increase the IL1B promoter activity and that is highly prevalent in African-Americans. Conclusions: To the best of our knowledge, this is the first study seeking for the association between CRC risk and IL1B gene in a haplotype context in a population-based association study in Colombia, an admixed population. Our results represent consistent evidence on how the identification of genetic biomarkers of susceptibility could be used to discriminate populations at increased risk of CRC development. Citation Format: Maria Carolina Sanabria-Salas, Gustavo Hernandez-Suarez, Adriana Umaña-Perez, Martha Lucia Serrano-Lopez, Myriam Sanchez-Gomez, Martha Patricia Rojas, Jovanny Zabaleta. Colombians with high percentage of African ancestry, carrying a specific IL1B haplotype, have increased risk of colorectal cancer. [abstract]. In: Proceedings of the Sixth AACR Conference: The Science of Cancer Health Disparities; Dec 6–9, 2013; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2014;23(11 Suppl):Abstract nr B23. doi:10.1158/1538-7755.DISP13-B23

Introduccion En Colombia la mortalidad por cancer colorrectal (CCR) ha aumentado. Los polimorfismos de un nucleotido (SNPs) en citoquinas pueden afectar su expresion genica aumentando la inflamacion y el riesgo de cancer. El SNP IL1B-511C/T se ha relacionado con cancer de estomago, mama, pulmon, cervix y colon-recto, pero los resultados no son consistentes entre las poblaciones. La evidencia respalda la importancia de la inflamacion en CCR pero pocas publicaciones han explorado su asociacion con polimorfismos de la IL1B. Objetivo Evaluar la asociacion del CCR y polipos adenomatosos (PA) con el SNP IL1B-511 en poblacion colombiana. Materiales y metodos Se genotiparon 324 CCR, 206 PA y 397 controles, pareados por edad y sexo, de un estudio multicentrico de casos y controles dirigido a investigar factores de riesgo para CCR. Todos los casos tenian diagnostico incidente de CCR o PA confirmado por histopatologia. Los controles fueron tomados en la consulta medica general y reportaron no tener sintomas gastrointestinales. Ningun sujeto estaba emparentado ni tenia antecedentes personales de otros canceres. Los participantes firmaron consentimiento informado, donaron muestras de sangre y respondieron cuestionarios. Se genotipo el SNP IL1B-511C/T mediante Taqman® SNP Genotyping Assay. Los analisis se repitieron en el 26% de las muestras (correlacion 100%). El equilibrio de Hardy Weinberg (HWE) se calculo en los controles. Los analisis estadisticos se realizaron mediante regresion logistica condicional ajustada por variables confusoras usando Stata v11.0. Resultados Los controles estaban en HWE; las frecuencias alelicas en controles, hombres y mujeres, fueron similares (C, 0,45; T, 0,55) y al igual que con CCR (C, 0,45; T, 0,55) y PA (C, 0,50; T, 0,50). Despues de controlar por factores confusores, no se observo ninguna asociacion entre los genotipos del SNP IL1B-511 con PA ni CCR invasivo. Al analizar por sexo y localizacion proximal o distal, se encontro que hombres portadores del alelo T presentaron mayor riesgo de desarrollar CCR proximal (OR 2,34; IC95% 1,42- 3,87; p Conclusiones El genotipo IL1B-511TT esta asociado con CCR proximal en hombres, lo que esta a favor de la heterogeneidad del tumor y su relacion con diferentes vias de carcinogenesis segun su localizacion. Para entender mejor el papel del gen de IL1B en el riesgo de CCR, se llevara a cabo un estudio de haplotipos del gen incluyendo los SNPs −31, −1464, −3737 y +3954 en colombianos.

Background: Single nucleotide polymorphisms (SNPs) in cytokines can affect gene expression causing an effect in inflammation and carcinogenesis. There are conflicting results in the association between IL1B gene markers with colorectal cancer (CRC). Most reports on the association of IL1B and CRC have analysed individual SNPs despite several studies have implied that studying the haplotype context is important to understand the biological effect in IL1B gene expression and carcinogenesis. Aim: To evaluate the association of CRC and adenomatous polyps (AP) with IL1B haplotypes in Colombian populations Methods: 308 CRC cases, 208 AP and 524 age-sex matched controls were recruited from six Colombian cities with different CRC risk in a multicenter hospital-based case-control study aiming at identifying the environmental and genetic risk factors for CRC in Colombia. Participants gave written informed consent, donated blood samples and answered guided-questionnaires. Subjects were genotyped for IL1B SNPs: -31, +3954, -3737, -1464 and -511 using TaqMan® SNP Genotyping Assays. Hardy-Weinberg Equilibrium (HWE) was assessed and statistical analysis was done using conditional logistic regression adjusting for risk factors and genetic ancestry. Linkage disequilibrium (LD) was calculated using Haploview 4.0 and D’ and r2 statistics. Recessive and codominant models were explored for haplotype analysis using STATA v11.0. The Ethics Board of The National Cancer Institute of Colombia approved this study Results: Among controls all IL1B SNPs were in HWE (p>0.05). We found one haplotype block including all 4 SNPs in the IL1B gene, except the IL1B+3954 SNP which was left out (MAF=0,14). IL1B-31 and IL1B-511 showed to be in high LD (D’: 0,998; r2: 0,948). Under recessive model, we found an association with an increased risk for PA and CRC with the -31C/-511T/-1464G/-3737C haplotype (OR 2.42 IC 1.21 - 4.84 p Citation Format: María Carolina Sanabria-Salas, Gustavo Hernández-Suárez, Adriana Umaña, Martha Lucía Serrano López, Myriam Y. Sánchez, Martha P. Rojas, Jovanny Zabaleta. Association between IL1B gene haplotypes and colorectal cancer risk in Colombian populations: a case-control study. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1343. doi:10.1158/1538-7445.AM2013-1343