Perfil de metilación de genes supresores de tumores como factor pronóstico en pacientes con leucemia mieloide aguda / Promoter methylation profile in tumor suppressor genes as prognosis factor in patients with acute myeloid leukemia

Existe creciente evidencia que apoya la presencia de un perfil de metilación específico para Leucemia Mieloide Aguda (LMA). La metilación de los islotes CpG en las regiones promotoras de los genes supresores de tumores es un importante mecanismo de control epigenético y participa en el silenciamiento transcripcional. Esto puede contribuir a un nuevo entendimiento de la biología de la enfermedad y vislumbrar nuevas oportunidades terapéuticas. Identificar el perfil de metilación de las áreas promotoras de un grupo de genes supresores de tumores; (p15, p16, ESR1, IGSF4, SOCS1, RARB y DAPK), y relacionar el estatus de metilación gen especifica o combinada con diferentes parámetros clínico patológicos. Se utilizaron muestras de sangre o médula ósea obtenidas al momento del diagnóstico de 33 pacientes con LMA, infantil y del adulto, recolectadas entre los años 1997 y 2008 en el Hospital Hernán Henríquez de Temuco. Se evaluó la presencia de hipermetilación mediante una Reacción de Polimerasa en Cadena Metilación Específica (MSP), previa modificación con bisulfito de sodio. La frecuencia de metilación de los pacientes estudiados fue de 88 por ciento, 27 por ciento, 27 por ciento, 21 por ciento, 15 por ciento, 3 por ciento y 0 por ciento para ESR1, RARb, IGSF4, p15, SOCS1, DAPK, y P16, respectivamente. La hipermetilación de P15 y RARb presentó una asociación significativa para una menor supervivencia en forma individual (p=0,03 y p=0,02), y combinada (p=0,002). No se encontraron diferencias significativas entre metilación y los otros parámetros clínicos analizados. Los pacientes con LMA presentan hipermetilación de la región promotora en algunos genes supresores de tumores, afectando negativamente la supervivencia. Esto pudiese eventualmente contribuir al establecimiento de un patrón de metilación determinado con utilidad clínica.

There is growing evidence than acute myeloid leukemia presents a specific methylation profile. The Methylation of CpG islands within gene promoters is a major epigenetic transcriptional control mechanism and plays a critical role in the transcriptional silencing of tumor suppressor genes. This provides new insights into the biology of the disease and it may offer novel therapeutic opportunities. To identify the promoter methylation profile of tumor suppressor genes (p15, p16, ESR1, IGSF4, SOCS1, RARB y DAPK), and to relate the percentage of methylation with clinicopathological features, as age, gender, white cell count, disease classification and survival rates. Bone marrow and peripheral blood samples were collected at diagnosis from 33 patients with acute myeloid leukemia, infants and adult, between 1997 and 2008 from Hernán Henríquez Aravena Hospital, Temuco, Chile. Methylation in the promoter areas of each tumor suppressor gene was analyzed using the mehylation specific polymerase chain reaction (MSP) technique using sodium bisulfite modification. The frequency of hypermethylation among the patient samples was 88 percent, 27 percent, 27 percent, 21 percent, 15 percent, 3 percent and 0 percent for ESR1, RARb, IGSF4, p15, SOCS1, DAPK, and P16 for each one. Methylation was significantly associated with an inferior overall survival (p=0.03 and p=0.02). When both genes are used, inferior survival is even more significant (p=0.002). There is no significant correlation between methylation and clinicopathological features.Patients with AML have hipermetilation at the promoter region of some tumor supressor genes, with a negative effect in the overall survival. This could eventually become part of establishing a characteristical methilation pattern with clinical utility.

Detección y tipificación de virus papiloma humano en lesiones preneoplásicas de cuello uterino / Human papillomavirus genotyping of cervical uterine preneoplastic lesions in a high risk area

The relationship between human papillomavirus (HPV) and uterine cervical cancer (UCC) is widely known and accepted. Aim: To determine the frequency of genotypes of HPV in cervical preneoplastic lesions in a high risk area of UCC. Material and Methods: Using a combination of PCR and Reverse Line Blot technique, 235 formalin fixed paraffin embedded samples, with diagnosis of low-grade squamous intraepithelial lesion (LSIL) or high-grade squamous intraepithelial lesion (HSIL) were genotyped. Results: HPV was detected in 61.2 percent of LSIL and 78.1 percent of HSIL. The main genotypes found were HPV 16, 18, 31, 45, 56 y 58. HPV 16 was the most common in both LSIL (18.1 percent) and HSIL (36.9 percent). HPV 16 or 18 were present in 25.1 percent and 47.1 percent of the LSIL and HSIL respectively. In both LSIL and HSIL, the predominant viral genotypes were those types classified as with a high oncogenic risk. Conclusions: HPV genotypes 16, 18, 31, 45, 56 y 58 were the most common in our series. HPV 16 and 18, viral types with high oncogenic risk and included in commercial vaccines, were found in 25.1 percent and 47.1 percent of LSIL and HSIL, respectively.

Genotipificación del virus papiloma humano en mujeres con adenocarcinoma cervical de la Región de La Araucanía-Chile / Human papillomavirus genotyping in cervical adenocarcinoma in the Region of La Araucanía-Chile

El virus papiloma humano (VPH) es el principal factor causal del cáncer cervicouterino (CCU). Así, detectar y genotipificar el VPH es importante para conocer la frecuencia de los genotipos presentes en la región. En este trabajo se estudiaron 44 biopsias de adenocarcinoma cervical (ACC). Para la detección del VPH se empleó una reacción de polimerasa en cadena anidada dirigida al gen L1 (RPCL1), para la genotipificación viral se utilizaron enzimas de restricción (Rsa I, Dde I, Pst I) y secuenciación. Se detectó ADN viral mediante RPCL1 anidada en 100 por ciento de las biopias. Se logró tipificar 38/44 casos: 81,6 por ciento VPH 16; 13,2 por ciento VPH 18; 2,6 por ciento VPH 33 y 2,6 por ciento VPH 18/33. Conclusiones: La metodología fue exitosa para identificar el tipo viral en 86 por ciento de las biopsias. Se observó una estrecha asociación ACC-VPH, especialmente con el tipo viral 16, detectado en 81,6 por ciento de los casos tipificados.

Human papillomavirus (HPV) is the main cause of cervical cancer. Thus, HPV detection and typing becomes important in order to know the frequency of genotypes present in the region. In this paper we studied 44 biopsies of cervical adenocarcinoma. For HPV detection nested polymerase chain reaction (PCR) was used to amplify the L1 gene. For viral typing restriction enzymes (Rsa I, Dde I, Pst I) and DNA sequencing were used. Viral DNA was detected by nested L1 PCR in 100 percent of biopsies; 38/44 cases could be typed: 81.6 percent HPV16; 13.2 percent HPV 18; 2.6 percent VPH 33 and 2.6 percent HPV 18/33. Conclusions: The technique was successful in identifying the virus type in 86 percent of biopsies. There was a strong association ACC-HPV, especially with the viral type 16, detected in 81.6 percent of established cases.

Detección y tipificación de virus papiloma humano en adenocarcinoma de cuello uterino mediante reverse line blot, Región de La Araucanía, Chile / Detection and genotyping of human papillomavirus in biopsies of uterine cervical adenocarcinoma

Background: The genotyping of Human Papillomavirus (HPV) will improve knowledge about the local epidemiological association of this virus with adenocarcinoma. Aim: To determine the frequency of HPV genotypes in biopsies of women with uterine cervical adenocarcinoma in a geographic region of Chile. Materials and Methods: Forty-one cervical biopsies with a pathological diagnosis of adenocarcinoma, corresponding to all women diagnosed with this cancer between 2002 and 2004, were analyzed. Viral gene Ll was amplified by PCRfor viral detection. HPV genotyping was carried out by a Reverse Line Blot technique. Results: Seventy one percent of biopsies were positive for HPV. The most common genotypes found were HPV 16 (61 percent), followed by HPV 18 (19.5 percent). Eighty seven percent of biopsies had a single HPV infection. Three patients had a multiple HPV infection. All of the latter were infected by HPV 16, associated with other three viral genotypes (45, 52 and 66). No low-risk HPV genotypes were found. Conclusions: In this sample of biopsies, there was a high prevelence of HPV 16 and a low prevalence of HPV 18, which historically has been related to adenocarcinoma. The genotypes found correspond to those described in South America.